Breeding the Orchid Dottyback

(and other marine fish)

Martin Moe, Sunday, October 20th, 2002

on #reefs

Speaker's Biography

Martin Moe is a marine biologist and acclaimed marine hobbyist and fish breeder. He has pioneered the field of marine fish breeding, having been the first to commercially breed Indopacific clownfish and gobies, as well as Atlantic angelfishes. In 1972, Martin established the first marine ornamental fish commercial hatchery: Aqualife Research Corporation.

Martin is also a noted author, with famous works including Breeding the Orchid Dottyback and the best selling Marine Aquarium Handbook. He has spoken at numerous local, national, and international conventions.

Presentation

Introduction

Hatchery Structure
Brood stock
Larva rearing
Grow out
Food preparation
Post larva
Juvenile
Adult
Algae and rotifer culture
Brine shrimp hatchery

Breeding Procedures
Establishment of the brood stock
Physical environment
Chemical environment
Nutrition
Spawning requirements
Maintenance and development of the eggs
Hatching
Larva recovery
Larva rearing
Handling late larva, metamorphosis, and early juveniles
Grow out considerations
Grow out tank requirements
Feeding
Environmental structure
Potential disease problems

Introduction
I could write pages and pages on this topic, in fact, I already have. It is difficult to condense such an intricate topic into a coherent and succinct presentation in the space and time allotted, so what I think will work best is to first present the basic outline (above) of the physical structure and the procedures and actions involved in breeding dottybacks (applicable to other species as well) in a small home based hatchery. Then I’ll take this outline and fill it in with a brief description of the structure or procedure. This will give you a total overview and then you can comment and question and I can try to fill in the details that pertain to your particular situation, interest, or insightful comment.

Hatchery Structure
Brood stock.
Dottybacks are small, usually aggressive, variably secretive fish. They seem to form loose pair bonds that are most expressed at courtship and spawning. At other times the pair bond is evidenced more as tolerance rather than cooperative living as with clownfish. Orchid dottybacks will also spawn in tanks holding large aggregations of juveniles that are becoming sexually mature. Several males may develop and spawn with various females in different areas of the tank; a sort of harem situation develops. Serious rearing efforts require keeping a male and female in a small, covered tank, 20 gallons is good, with a lot of structure that can serve as hiding areas for the female and spawning dens for the male. Good spawning dens can be made from PVC pipe. Although a separate brood stock tank is best for observations, control, and recovery of the larvae, successful spawning and larva recovery can be done in a reef tank, but with some difficulty and less success in larva recovery.

Larva rearing
A separate tank is required for larva rearing. 10 gallons will work for small numbers, 10 to maybe 50 or so, 20 to 30 gallons is required for large numbers, 100’s of larvae.

Grow out
At and after metamorphosis the juveniles require a bottom environment. In home hatchery situations it is best to transform the larva tank into an intermediate grow out tank by adding live rock and pvc structure to the larva tank. Within a couple of weeks, the juveniles should be transferred to a larger grow out tank, 30 to 50 gallons depending on numbers, set up with live sand and pvc structure. (pvc pipe is good structure because the juvenile dottybacks can not sequester themselves in tiny holes and it can be removed from the tank without struggling to remove the small fish from their hiding holes.

Food preparation
Along with the proper physical and chemical environment, this is the key to successful rearing of marine fish.
Early larvae – enriched rotifers
Late larvae – enriched rotifers, enriched brine shrimp, copepods, wild plankton, shaved shrimp particles are all useful. Some specialized larval foods may also be good just before metamorphosis.
Post larva – shaved shrimp, some processed frozen and flake foods, juvenile enriched brine shrimp
Juvenile – shaved shrimp, some processed frozen, variety!
Adult – same as juvenile

Algae and rotifer culture - Basically important for successful rearing of larval fish. See F. Marini’s recent articles in A.A. I found that I could easily maintain rotifer cultures with a vegetable juice formula. Omega-3 fatty unsaturated acids are probably the component in wild plankton (mostly the early developmental stages of copepods) that makes the difference in death or survival of larval dottybacks. Selection of the right micro algae to culture (Nannochloropsis oculata) and/or the right commercial supplement will make the difference between success and failure in dottyback culture without wild plankton.

Brine shrimp hatchery – Simple half-gallon plastic soft drink bottle hatchery works well.

Breeding Procedures
Establishment of the brood stock – Get several of the smallest individuals you can find and place them in a covered tank with a lot of structure. Observe carefully, remove any harassed individuals. As they age, one will grow faster and become the male. Within a few months, a breeding “pair” (a male and female that tolerate each other, like some marriages) will form. The male selects a den area, they court, the female enters the den, spawn occurs, an egg mass results, the male tends the eggs, the eggs hatch in four days, they spawn again two days later. 400 to 800 eggs are usually produced.

Physical environment – A lot of structure and den structures for the male. Good lighting, reef quality lighting not necessary, temperatures in the high 70s to low 80s F,

Chemical environment – good water quality important.

Nutrition – see above. Dottybacks require a lot of enrichment in the diet of the mid larval stage. I found that wild plankton made all the difference in my rearing work with orchid dottybacks. I supplemented with wild plankton roughly between days 8 to 20. I was not successful without wild plankton, but then I did not make a great effort at rotifer enrichment.

Spawning requirements – regular feeding, lots of structure

Maintenance and development of the eggs – the male takes care of this. His slime on the eggs (perhaps some antibiotic peptides are included here) seem to keep the eggs in good shape. He can take care of the eggs much, much better than any aquarist. Leave the eggs with him, he’ll take care of them and hatch them very well. It may take him a few tries before he figures everything out. You’ll know he has eggs in his care when he seldom leaves his den.

Hatching – the male does this at night, usually about an hour or two after the lights go out. A really interesting process. The larvae stream out of the den and accumulate near the surface.

Larva recovery – Shine a small flashlight at a corner of the tank, turn off water flows (don’t forget to turn them back on!), and the larvae will accumulate in the light. Use a dip cup or a siphon to collect the larvae. You won’t be able to get them all, but no problem in getting enough for any rearing work. Transfer them to the larval tank that is already set up with water and air stone.

Larva rearing – Separate tank required, use just a bare tank and one or two air stones to move water around. A black plastic cover around the tank is good for providing a background to make seeing the food organism by the larvae easier. Add algae (if possible), not a lot, just make the water a very light green, the day before hatch. Add rotifers, about 3 to 5 per ml to the tank the morning of the day after hatch. Dottybacks go through rotifers like a ten year old goes through sneakers, so watch carefully and add rotifers as often as required. (Depending on the number of larvae and the size of the tank).

Handling late larva, metamorphosis, and early juveniles – Larval dottybacks can be moved if necessary, but this is not good. They shouldn’t be moved until well after they have developed their magenta color and are acclimated to the bottom. They can then be moved with a soft fine mesh net like most other fish. Add structure to the larval tank when they begin to pick up color and start to stay in the corners of the tank. Small pieces of live rock provide structure and biological filtration. Pvc pipe pieces add good and easily removable structure. After all or most, depending on numbers and tank size, of the dottybacks have metamorphosed, they can be moved to a grow out situation.

Grow out considerations
Grow out tank requirements – A tank, 20 to 50 gallons, set up with live rock, live sand, whatever auxiliary filtration suits you, works fine. Again, a lot of structure!
Feeding – as above
Environmental structure – Live rock (minimize rock with tiny holes), ceramic structure (coffee cups?), pvc pipe, etc.

Potential disease problems – A big topic. Most serious, protozoan parasites (Amyloodinium), and bacterial toxins (toxic tank syndrome) are the most rapidly lethal of the problems I have encountered. Keep an extra tank handy so that the juveniles can be moved quickly and treated if necessary.

For more information on rearing the orchid dottyback see my 1997 book on the subject, titled Breeding the Orchid Dottyback; An aquarist’s journal. Available at Amazon.com

Questions and Answers

I added a wild caught P. fridmani to a 155gal tank and I'm wondering what my chances are of adding a mated pair to the tank without aggression?

What age do dottybacks become aggressive to one another and should not be mixed with more than 2 per tank?

Actually a complex question. I often had many individuals in one tank, 20 to 300. And there was little aggression and evern spwaning, at age 4 months. So many can exist together. but often 3 to 8 will fight badly. And these were reared together, which may be a factor.

How long do you think it will take before most of the commonly kept ornamentals will be able to be bred in captivity (best guess)?

Best guess, if a good first food is found, 3 to 5 years, if not maybe never. Wild plankton can serve as a first food for the small egged fish, but that will probably not be adequate for large scale rearing.

Martin you mentioned "Some specialized larval foods may also be good just before metamorphosis"....any recommendations whats these specialized foods are?

By first food I mean something smaller than rotifers.

Would you consider cod liver oil to be the best source available to the general public of OMEGA-3 Highly Unsaturated Fatty Acids?

There are some commercail larval foods compounded for shrimp and some fish. some of these or something made like these is what I referred to.

What other phytoplankton species do you recommend looking at besides Nanno? Frank Marini mentioned in one of his Advanced Aquarist articles that some species of phytoplankton have antibacterial properties.

No, I think not. I have used cod liver oil and menhaden oil but a preperation like Super Selco that is made expressly for larval marine organisms is best. T-Isochrysis is also a good high in fatty acid algae, that is a very good one to use, by itself or in combination with Nano.

What is menhaden oil?

You take a menhaden, a small clupoid fish that is in (was) great abundance in the Atlantic and squeeze it hard. It makes a good fish oil.

Do you have any recommended books for more information on breeding setups (besides your own of course)? :)

Right, besides mine.... Actually there are two, the one by Joyce wilkerson on clownfish, and the one by Frank Hoff on clownfish. The one by Joyce is more hobbyist friendly than Frank's, but both are good.

Tell me more about your rotifer cultures and the feeding vegetable juice formula. What is that formula?

Well, maintaining microalgae cultures, especially pure cultures is a real task for a hobbyist, especially one with a life. I tried to develop an easier way to maintain rotifer culture and came up with a formula based on V8 juice. This formula is in the article in the most recent AA that I wrote on ciliates.

Have Golden pearls been tried as first foods? In fresh water they are used for raising fish but it seems as though all we use it for is coral food. Has this been tried already?

I haven't tried golden pearls, I'v heard of that food however, and there were good comments. I think it would be best, not as a first food, especially not for small egged fish, but as a supplement from mid to late larvae PERHAPS, and most likely in the early juvenile stage.

Follow-up to an earlier question: would adding a second dottyback to a system with one dottyback result in mated pair?

Maybe... A big maybe. It depends on the age and sex of each dottyback. Sex in dottybacks is interesting. I think it is condition of opportunity. A big dottyback is certainly a male and small one may be a male or a female or if small enough, not sexually determined. The best chance for adding a dottyback to an established fish, is to add the smallest individual that can be found.

Can you speculate what would be the next "good" fish to attempt to breed for the home hobbyist (beside clowns, gobies, and banggai cards)?

Probably the best would be some of the unusual gobies or the blennies. These are mostly substrate spawners and the eggs and and larvae can be observed and recovered fairly easily. And the dart fish. the firefish or fire gobies. Now those are some fish that would be great to breed for many reasons, AS I understand it, they lay eggs in dens like dottybacks, but I don't know how easy the larvae will be to rear. This is one group that I would love to work with. And the jaw fish, another rather easy fish. I reared them in the 70s. Not difficult and most interesting. Yep, It would be one of these. mm

Thanks for the great talk, Martin!

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