Of Interest to Aquarists

There are many mailing lists that pertain to the aquarium hobby. There are many more that sometimes have information of interest to aquarist. Subscribing to most of these myself I recieve an abundance of e-mail. Here are some threads that might be of interest to you. These are just snips from some of the mailing lists, to become involved and get all the messages you can subscribe to these mailing lists. If you don't know how drop me a line.

The best new site has to be Richard Pyle's Dive log . He's diving and photographing in Palau and keeping a daily log online for all to see. This is a definate must for Marine Aquarists

• Breeding Koi
• Clownfish
• sex colour differences in blue damsels
• Aiptasia question
• Lysmata

Breeding Koi

Dear anonymous koi-aqualer,

Breeding koi is the same as breeding common carp. Some practical tips, in brief:

1 . One month before the start of reproduction season of common carps in your area, you have to separate males from females. Sexing of spawners can be easily done 2-3 months before reproduction season;

2. When the water temperature is constantly above 18 Centigrade (for temperate areas) you transfer the two sexes in the same water tank (2 males with 1 female, or approximately in equal weight proportions). The recommented fish stocking density is 1 fish/sqm. Simoultaneously we introduce in the spawning tank, floating aquatic-plant collectors or collectors from other appropriate materials as a nest for the collection of sticking eggs. Flowing water in the spawning tank would be also required. Continue feeding;

3. Make the above transfer preferably in the morning and avoid injuries and stressing the fish. Within 1-3 days, but generally the next day early in the morning, all kois will spawn. 1 kg females produces a variable number of eggs, but generally between 100-200.000. Collectors of eggs have to be replaced and transfered to the hatching out tank (see below) every 1-2 hours during spawning;

4 . Hatching out of collected eggs has to be done in another tank, with clean and running water, away from genitors, or in the "open air" in an appropriate, constantly humidified (by fine spraying of clean water) environment. This latter method would not get any fungi (Saprolegnia) problems. Hatching out of eggs will take place within 2-6 days between 30 to 15 C, respectively, or 75-85 day-degrees accumulated temperature. Best WT for hatching-out ratio and survival of larvae is achived at around 20 C, but constant. Hatching-out ratio varies between 30 and 80%;

5 . Just before hatching-out transfer the collectors (with the eggs still attached to them) to the water of the fry rearing bassin. The hatch-out larvae have to be kept in this bassin for at least 10 days and up to 30 days. Feeding the hatch-out larvae is another long story, that you must discover yourself, reading appropriate texts. Andreas Laggis

Clownfish & Damsels br@kplace.monrou.com

Hi all,

I just returned from the local pet store where I was watching the large display tank and realized the two percula clowns which have been been living in a beatiful frogspawn coral for years have begun spawning at the base of the coral. It was the first time I had actually seen clownfish eggs up close. They were much larger than the damsel eggs from my chrysiptera taupou. Now I can see why my damsel fry didn't take to rotifers as a first food since they are only about half the size of clownfish fry. I just started scaling up my greenwater/rotifer system again to try some of the supplements (Selco, etc.) with the rotifers to see if that helps, but now I think it may be a futile effort. Any opinions?

Jon

BTW, I really enjoyed the BR web site! nice work :)

>>>>>>>>>>

I'd suggest trying the "S" strain of rotifers if your not already doing so. Then when you divide the cultures for feeding/harvesting, try starting some cultures with "filtrant" which passes through your seive. This will take some time but you can get a smaller sized cultured organisms (maybe ciliates since I think most everyones' cultures have ciliates present).

Never give up!

> BTW, I really enjoyed the BR web site! nice work :)

We hope it will continue to be useful. It does seem to be attracted new members <g>

Stan

I've done some research (based on a limited pool of references) on Andreas comments/questions. Hence the follow-up:

> Your suggestion to Jon for "S" strain or "S" type rotifers can be proved to be the right one. "L" type rotifers are large enough, even up to 180 microns and as you said maybe too large for the damsel mouth opening. The question then comes to how we produce the "S" type rotifers?

The "S" strain (or morphotype) is 110 - 230 um lorica length ( the hard thickened body wall) The S- and L-type rotifers are distinguised by size,shape and shape of anterior spines (Ito, Sakamoto, Hori, and Hirayame, 1981)

The population is a mixture of S- and L-type and the frequencies is dependent on the season. (Pi, 1991) ... <unfortunately Pi's paper doesn't say what the seasonal differenecs are>

Green mussels!!! The veligers at 24 hours are 55 - 60 um. The mussels can be induced to spawn by temperature jumps.

The mouths of some species are too small for rotifers and they can be fed mussel veligers.

Mussels are induced to spawn by first immersing in 33 - 35C for 1/2 hour followed by 1/2 hour in 23 - 25C. Then returned to tanks containing 40 liters. Spawning takes place 30 - 60 minutes. Males are placed first and then removed immediately after milting, then females are placed in tank. Spawning is complete 2 - 3 hours. The eggs sink and are removed by siphon. The author Lim is from Singapore, so although not stated we can hypothesize that the ambient temp is ~ 26 - 27C. Eggs develop into trochophores in 7 - 8 hours.

Doesn't say how to sex mussels, but after an initial spawning this should be simple to determine. So...anybody know of a source for Green mussels? (tropical?)

OK...back to rotifers <g>

S-type: salinity 25 ppt, feeding _Tetraselmis tetrahele_ or Nannochlopsis oculata_ no mention of temperature :(

> I have heard that rotifers cultured in high water temperature, say 28 centigrades, will give you a 30% population of "S" type rotifers. I understand from this that any culture of rotifers is a mixture of L and S type rotifers. When the culture temperature is at the higher levels the "S" type is proliferating more than the "L" type and vice versa.

I did find, "The L-type rotifer grows best under temperate conditions and low salinity..." (Hagiwara, et al, 1989) although no quantifiers provided.

Arnold and Holt, 1991, indicate 18 ppt @ 24 - 25C...unfortunately the paper doesn't indicate which strain, other than it was obtained from NMFSL at Scripps, La Jolla, CA.

Ah-hahh!! Maeda and Hino, 1991. " Growth rates of L- and S-type rotifers differ at different temperatues. S-type grow faster than L-type above 25C....below 25C the growth rates of L-type rotifers are higher. Optimum temperatures for cultures of L- and S-typr rotifers are approximately 25 and 30C respectively. ....Optimum chlorine concentration ... is 6 - 10 ppt, ... 18 ppt chlorine (normal seawater), too high for rotifers grown at 6 - 10 ppt. For this reason, rotifers are generally reared in normal seawater."

All of this came from the Proceedings of the US - Asia Workshop: Rotifer and Microalgae Culture Systems, 1991.

Stan

....Optimum chlorine concentration ... is 6 - 10 ppt, ...

> 18 ppt chlorine (normal seawater), too high for rotifers grown at 6 - 10 ppt. For this reason, rotifers are generally reared in normal seawater."

Would you clarify part of this quote for me, please <G>. The next to the last and last sentence has me confused. If "Optimum chlorine concentration ... is 6 - 10 ppt, ... 18 ppt chlorine (normal seawater), too high for rotifers grown at 6 - 10 ppt." This totally seems in cotradiction of the last sentence where you quote/state that "For this reason, rotifers are generally reared in normal seawater."

Larry

I believe (having reread the paragraph in the paper) that the rotifers are essentially brackish. The ppt chlorine is an unusual mode, but since 18 ppt chlorine is normal seawater I assume that this is equivalent to 36 ppt salinity. Thus although optimum salinity for rotifers is 6 - 10 ppt chlorine (12 - 20 ppt salinity ?) the difference between optimum conditions and rearing conditions for the target organisms is too great. So... the rotifers are cultured under less than optimal conditions.

Osmotic shock would be extreme and potentially fatal to the rotifers when fed to the larval fish.

At least that's what I get out of it!

Stan

sex colour differences in blue damsels

I am rather confused about the colour variations in the Blue devil-Chrysiptera cyanea and the yellow belly damsel -C.taupou.Some of these colour morphs could be sex indicators,while others could be just geographical or subspecifical character.Does anybody have any observations on this subject?.I find it important as a tool for mating true pairs while at the same time avoid unwanted crosses between unrelated populations.

C.cyanea

Fishes showing yellow coloration They are quite distinct and called "jewel".I haven't observed sex differences in this morph.

All blue fishes

Some show blue fins,with a darker edge particularly in the caudal fin.Other sport colourless fins.I think that blue finned are males and colourless females.I recently bought one of such pairs which were sharing a tank in a store,with only some mild agression,and they soon spawned and had larvae hatching. But in some atlas blue finned and colourless are considered as different geographical populations.Furthermore an importer told me that he gets lots all of one phase or the other,not mixed.I imagined they could be sorted by exporters but he disbelieves that.Too much work for such a cheap fish.And blue finned are not more expensive than the others.I saw colourless finned looking like males(large,long body and fins,dominant behaviour)But I still have to see a blue finned female. Also some fishes have an eye spot close to the rear edge of the dorsal while others don´t but I don´t know if it is relevant to this matter.

C.taupou

I had a pair which had larvae hatching and sexes were very distinct. The male has a whitish dorsal fin with a dark blue edge.The female has an all sulphur yellow dorsal fin.

In Dr Allen "Damselfishes of the south seas"page 149,one can see a pair of taupou male on top.The fish are referred as Glyphidodontops cyaneus and they are both said to be females!.How could Dr Allen know? Then a "male"shows in page 152 which looks like a "jewel"C.cyanea. Page 400 of Dr Burgess mini atlas shows a "male". Recently many taupou were imported here and all were yellow dorsals. Is this character a sex indicator or I had by chance got a pair of two individuals of two different populations?.

So I expect your experiences in this matter,and if you don´t have any,remember next time you go to the store to check all C-cyanea and taupou to try and solve this chromatic mistery!

Luis.

Stanley D. Brown wrote:

> In researching the taxonomy of the "blue damsels" I have come up with some information which may be of interest, some of which is conflicting.

According to ITIS the family Pomacentridae contains 22 genus: pertinent to this present topic would be _Abudefduf_, _Glyphisidon_ and _Pomacentrus_.

You will no doubt note that _Chrysiptera_ is omitted... ITIS lists this as being invalid with _Glyphisodon_ as the Accepted Name.

_Chrysiptera cyanea_ (Quay and Gaimard, 1825)

"Usage: Invalid"

> "Valid Scientific Name: _Glyphisodon cyanea_" Glyphisodon sounds masculine.Shouldn´t the spelling be cyaneus?

Now on to other "Blue Damselfishes"

_A. hemicyaneus_ (Weber, 1913) is listed and validated as _C. hemicyanea_(Shen, Yu & Yeh, 1968) however, no listing of Shen, et al. is found.

I have seen C,hemicyanea many times called C.parasema.

Thanks for the taxonomical updating.For some reason these fishes,the yellow tail damsel and the blue devil have changed scientific names so often and been allocated to so many genera that a great confussion was generated. This is surprising when we consider that these two fishes are two of the most popular marine aquarium fishes.Everybody knows them,most people has started with them,and their pictures are depicted in most books,even in the covers!.

Luis.

Aiptasia question

br@kplace.monrou.com

First in response to Kevin's reply, I wasn't so much questioning reproductive strategies (i.e., dispersal) rather, looking for a way to manipulate the organism to produce "more" replicates.

> >Has anyone come across any theories as to what determines whether an > >Aiptasia asexually reproduces by pedal laceration rather than "live birth"?

Dave said:

> Kempf makes the following suggesting in: > Berghia verrucicornis , a nudibranch predator of the aquarium > "weed" anemone Aiptasia > > We have found that "bleached" Aiptasia, those that have been kept > in the dark long enough to lose most of their symbiotic algae, > provide a better source of tiny anemones since they pedal lacerate > and produce very tiny regenerates much more frequently than > symbiotic anemones. > > Sounds like we're doing some of the same work. I'm very interested in > an Aiptasia farm for Berghia culture. The paper I mentioned above has > the following reference at the bottom. It's tough for me to get to > the university library. Any chance someone with easy access would be > willing to Xerox me a copy? I'll pick up Xerox/mailing costs. > > Hunter, T. 1984. The energetics of asexual reproduction in the > symbiotic sea anemone Aiptasia pulchella (Carlgren > 1943). J. Exp. Mar. Biol. Ecol. 83: 127-147. >

> >PS this curiosity stems from working with _Berghia_ more than my affinity > >towards Aiptasia <g> > > Which brings up the point - Anyone else on this list working with > Berghia? > > Thanks to Gary Moss, as of May 3rd I have Berghia to work with again. > Stan, do you have Berghia or are you just researching?>

Both

I have 3 adults and at this point am unsure if they have reproduced yet as I haven't been able to follow the life cycle through (so as to know what I'm looking at/for). This is my second attempt. The first came from Jon and I placed them into a large tank which is seriously infested...I never saw them again after the first couple of days nor did the Aiptasia population seem to suffer much! Gary recently was able to spare 3 which are now in a separate tank (100 l) with lots of Aiptasia, plus I have a 37 L tank as a separate "farm" where I have other Aiptasia growing. I've been feeding my excess rotifers to the Aiptasia, which is easier (since I have a surplus) than hatching Artemia.

I'd be interested in seeing a copy of Hunter's paper if it should become available.

Stan

Lysmata

br@kplace.monrou.com

>I cruise the web from time to time looking for more information about >Lysmata and I happened across your post in an archive (I know this is an >ancient thread).

Ah, this is an ancient thread indeed. We had a discussion about this topic for a while, but since no one had any concrete evidence one way or another (we were all just blowing smoke for our favorite hypothesis), the "debate" slowly died out.

>My two bits worth are that Lysmata amboinensis is >indeed a simultaneous hermaphradite. I base this statement on about 2 >years of observation of several "couples." I have watched them mate, >spawn, incubate, hatchout and moult. The tell-tale signs of >simultaneous hermaphradism include: >1) Under the carapace you can see the greenish egg-mass (vitellogen) >developing over a two week period. It is only depleted when eggs are >deposited on the pleiopods of the newly moulted (and mated) shrimp. If >the "female" deposited eggs on the "male," one would expect a depletion >of the vitellogen on the opposite shrimp at that time. >2) I have observed the mating behaviour and they alternate the roles. >The newly moulted shrimp always plays the female role (and subsequently >loses "her" vitellogen when "she" deposits eggs) and the other shrimp >always plays the male role (and does not lose "his" vitellogen).

OK, I freely admit that I was just throwing alternative ideas out there for people to consider as possibilities in that old message, especially on the trading eggs idea (although some species actually do that). I have watched my Lysmata a lot, and haven't seen anything that would convince me that they are "trading eggs" either.

Like you, I have also spent a couple of years observing and breeding a couple of Lysmata species, but am still hesitant to accept that these animals could be hermaphroditic, because I have yet to see any conclusive evidence. I have several pairs and of Lysmata (4 wurdemanni, 2 ambionensis) shrimp plus an extra individual of L. ambionensis. In each of my pairs of L. wurdemanni there is some size dimorphism, and I have never seen the smaller males carrying eggs, nor have I ever seen the larger females attempt to copulate. In the L. ambionensis I have one pair that are inseparable, but which pretty much ignore the group of three. In that 3-some, 2 individuals develop eggs regularly and both attempt to copulate with the other, but the third individual (which I consider a male) has never developed eggs. It does, however, regularly copulate with both of the other shrimp (which I term females), and occasionally with the other solitary pair.

I am still not convinced that Lysmata are simultaneously hermaphroditic because it would be the first reported case of a simultaneous hermaphrodite among Decapod crustaceans (in fact, among Eumalacostracans as far as I know). Although some Crangonidae species have separate sexes (Hoeman 1982), most are protandrous hermaphrodites, although male characters and function may be suppressed or completely absent in some individuals (Allen 1959). Butler (1980) gives a description of sexual dimorphism in caridean shrimps: the female has small processes with hooklike setae (the appendix interna) on the inner edge of the endopod on the second pleopod, whereas the male has another process (the appendix masculina) between the appendix interna and the endopod, as well as small hook-like setae on the tip of the inner lobe of the endopod of the first pleopod. These structures may exhibit transitional stages between the active male and active female stages, and the initiation of sexual maturity and sex reversal are under hormonal control (e.g., Carlisle 1959a,b,c, Hoffman 1969, Klek-Kawinska & Bomirski 1975). It just seems that although everyone claims these shrimps are simultaneously hermaphroditic, there is no evidence for that claim, and the more likely explanation of long-term sperm storage is basically discounted.

>I am interested in whether there is a discussion group still talking >about these shrimp. The one that I was a part of has fallen apart. Too >bad, we were coming close to reproducing Lysmata amboinensis ("ambos"). >I've gotten them out to 30 days and another group member had achieved >180 days. Any information that you could give me would be appreciated. >Ray H. Kamps

180 days seems to me WAY too long for these larvae to be planktonic - they must be doing something wrong! Riley (1994) reports that larvae of L. wurdemanni settle between 45 and 60 d, which still seems a bit long to me, but is at least in the range I would expect. Most caridean shrimps on this coast brood the naupliar stages (as does Lysmata), and there range between 3 and 8 zooeal stages depending on species (which shouldn't take anywhere near 180 d). I've kept the larvae myself for about 30 days also (and I thought that they were competent then - but I wasn't keeping track of how many naupliar molts they had been through), but I've been trying to raise the larvae entirely on artificial foods (I'm not sure why, but I want to see if it can be done). I was going to try settling the larvae a couple of weeks ago, but had to go out in the field for several days for my research, and when I returned all the larvae had died (oh, well - next time). I would guess that if the larvae remained planktonic for 180 days that they were either seriously malnourished and had not yet reached competency, or had reached competency, but had not yet been exposed to an appropriate cue for settlement. You might want to check out Goy (American Zoologist, v.30, n.4, (1990): 128A) for some info (albeit very little) on inductive substances for Lysmata larvae - or try KCl shock (Pechenik & Gee 1993, Pearce & Scheibling 1994, Wendt & Woollacott 1995) or some other method for inducing settlement (I think I explained some of this my Journal of Maquaculture article, but I'd have to go back and look now). As for other places of interest - the Breeders Registry (br@kplace.monrou.com -or- http://www.breeders-registry.gen.ca.us) is

always interested in such discussions (I've already CC'ed this reply to the group because others may also be interested in the discussion), and as far as I can tell includes many of the most knowledge aquarists in the hobby. Check it out -- especially Riley's article on L. wurdemanni reproduced with permission from SeaScope (1994) --

(http://www.breeders-registry.gen.ca.us/Reprints/SeaScope/v11_sumr/shrimp.ht

m).

I guess I could try to get in touch with someone at Texas to find out the answer, because Holt and/or Riley haven't published anything else about Lysmata (at least not in any scientific journals -- I can pass along their citation list, mostly on Red Drum larvae, if you're interested, though). If you're not a member of breeders registry, you probably ought to join -- the information in JoM is IMHO worth it.

Good luck, Rob Toonen

Regarding the length of time Lysmata remain planktonic: Karen Brittain has reared Lysmata and Hymenocera shrimp here at the Waikiki Aquarium. As I recall they take about 6 weeks to settle out.

Bruce

>Robert,

>I published a couple of articles in Freshwater and Marine Aquarium magazine a couple of years ago on Lysmata amboinensis. That species seems to me to be simultaneous hermaphrodites as does L. rathburne and L. debelius which was raised at C-Quest Ornamental Marine Fish Hatchery in Puerto Rico. I cannot add anything on L. wurdmani. In culturing L. rathburne and L. amboinensis, I'm convinced that the general population is simul. hermap. BUT in one L. rathburne from one of my hatches a strange thing happened to ONE shrimp. One shrimp did not progress beyond being a permanent male. Based on my observations, the shrimp can father eggs for a month or two before they can extrude eggs, generally. But once they begin extruding eggs, they are simultaneous hermaphrodites. My estimation of the ONE strange shrimp was that I had done something wrong during its culturing that stunted its growth and that made it impossible for him to fully mature. I'd have to resort to my notes or run additional experiments, but as I recall, L. amboinensis ALSO, in addition to being simultaneous hermaphrodites, store sperm as was evidenced by one or two egg clutches which were fertile in shrimp that were separated.

>I do a lot of work with C-Quest Hachery and I would not make a blanket statement that ALL Lysmata sp have the same reproductive behavior. I've not worked with all the Lysmata species and some may be different. At C-Quest we have found a few gobies that have reproductive or larval behaviors that are NOT consistant with the genus they are currently classified in. The same may be true for certain Lysmata species.

>In summary, my experience is that L. amboinensis is a simultaneous hermaphrodite with an ability to also retain sperm. L. rathburne is a simultaneoud hermaphrodite with an occassional "runt" that only reaches male status. L. debelius is a simultaneous hermaphrodite with no enough information to define any quirks at this point.

>Joyce

Joyce,

I have read your articles, and I have bred some of these shrimps myself (L. wurdemanni, L. amboinensis and L. ?multicissa?), and while I appreciate your accomplishments and agree that the behavior of at least L.a. (but certainly not the other two species which both exhibit sexual dimorphism) seems pretty consistent with simultaneous hermaphroditism, I will continue to play devil's advocate; I simply have not seen any concrete evidence of simultaneous hermaphroditism in these species. As I said in my reply to the original poster, this would be a new discovery for at least the Decapoda, and to the best of my knowledge the entire Class Malacostraca (over 20,000 currently described species), which with the exception of a few protandrous hermaphrodites, is nearly entirely gonochoristic (Brusca & Brusca 1990). Thus far, all the "evidence" presented to support simultaneous hermaphroditism is anecdotal stories to the effect of "I stuck 2 shrimp in a tank, and both developed eggs." Although that is the first step, it is very difficult to prove simultaneous hermaphroditism, because the alternatives (the most likely but not lone possibility being sperm storage, especially if coupled with sequential hermaphroditism under hormonal control) are exceptionally difficult to discount. Given that, I am not trying to be unreasonable (although I probably appear that way), but am just trying to point out that there are alternatives which remain entirely consistent with the observed data, and which need to be discounted before we should accept that some Lysmata species are the lone exception to gonochorism among the decapod crustaceans. Until someone demonstrates that a single individual has both functional testes and ovaries it is simply not possible to discount sequential hermaphroditism and sperm storage (especially as there is no way to determine whether sperm transfer actually occurs during copulation) as a reasonable alternative to simultaneous hermaphroditism. If someone demonstrates that there are indeed fully developed and functional male and female gonads within an individual, I will gladly admit that I was wrong, and apologize for having been such a pain in the ass about these details, but until that time, I'm afraid that I will remain a skeptic. Of course, I'm extremely hesitant to sacrifice and section one of my pets to convince myself of the possibility and keep hoping that someone else will do the dirty work for me....

Aside from that, I also find it very interesting that you have a terminal male (of a different species - mine is a L.a.) in your experience. I purchased my shrimps at the same small size, have raised them in the same aquarium and treated them in exactly the same way, and never really considered that the behavior was due to some failure on my part to provide that individual with something vital to maturation (although that is certainly another possibility). Is your shrimp an "odd-man-out" also? I ask because this is actually a common strategy in sequentially hermaphroditic fishes, like the blue-head wrasse, <italic>Thalasoma bifasciatum</italic>. Although most individuals begin their lives as females and only the largest individuals develop into the terminal phase male, some individuals become males immediately upon reaching sexual maturity, but do not change phase. These individuals then act as females (and retain the "immature" coloration of females), but during spawning rushes, they release sperm rather than eggs, and likely have a reasonable fertilization success (albeit lower than that of the large terminal phase males) without the costs associated with phase changes. The same "sneaky spawner" strategy is employed in many birds, reptiles, amphibians and mammals. I wonder if some of the caridean shrimps are doing the same thing?

Inverts are so cool. I love this stuff!

Rob