Breeding fish… genetics

[Magnum Man]

So obviously breeding for a trait like albinos requires some thought about genetics, but seems like generally fish keepers don’t seem to worry about that as much as a farmer, breeding sheep, cattle, or pigs… does the sheer number of fish eggs provide that diverse of genetic material???

Was reading a thread today about someone who got 2 juvenile cichlids, and were hoping they had a male and a female, so they could try to breed them… I’m planning on trying to breed some Tilapia this winter… in both these situations, there is likely a pretty good chance, that these fish came from the same parent groups… my Tilapia came from a big breeding supplier, but because they are lotted, may have come from the same male… the other cichlids if purchased from a local fish store, may have been bred there, or supplied from one of their customers, and could be from the same brood or same parents… is this kind of thing ok, or if you were thinking about breeding, should you be getting fish from the most likely different sources available

Thoughts???

 

[Colin_T]

Generally if you buy fish from a shop or breeder they will be related (probably brother and sister). If you get wild caught fish, they could be related but much less likely than anything from a fish farm, which supplies shops.

If possible, try to get unrelated bloodlines for breeding to maximise genetic diversity and reduce the health issues associated with inbreeding. To do this you might need to find shops or breeders that have fish from different suppliers and if possible get the fish from different countries if you can.

 

[Magnum Man]

That’s what I was thinking… but it must happen more n the aquarium trade than any other raised animals… I have 5 king tiger pleco’s right now… young juveniles… 3 in one tank, 2 in another… could be any fish we buy several in a group, if purchased same place and time… all probably related, yet we are happy, if we end up with a breeding pair, at maturity… I just mentioned the king tiger pleco’s, as they were not purchased to breed, but they breed in aquarium’s pretty regularly… the ones I bought were tank raised, and likely from the same brood… who’s parents may even have been from the same brood???

 

[TwoTankAmin]

When I first began breeding zebra plecos in 2006 I asked the expert person who facilitated my acquiring the fish the same question. She was responsible for assembling the group for the person from whom I purchased the fish. i asked her how many generation one can go before they need to add in new genes to prevent inbreeding. Her answer was at least 5 generations.

I have never gotten beyond two generation for any of my species. I have almost never had a spawn with any defects, I did get one spawn years back from my L450s where all the offspring had a deformed right pectoral. I gave them to a friend who understood their condition since I could not keep them due to space. She took them rather than have me euthanize them. Oddly enough, a number of months later a power failure hit her fish room and she lost the 450s as well as a bunch of other fish.

When it comes to breeding fish and being aware of and taking action to prevent inbreeding, good breeders do so. In relation to this I have always worked with groups of fish as opposed to pairs. When I have a diverse group of indivduals in a breeding colony, I let them decide who will spawn with whom. This is how I set up the breeding tanks for plecos.

I put in an assortment of caves in terms of shapes. size and positioning and then let them work out who claims what. I have never line bred any fish in an attempt to fix a trait. Many of my fish take a number of years to reach spawning age/size. In order to get through just 3 generations would take at least a decade. I came late to keeping fish and even later to breeding them. Considering I did my first group in Apr. 06, I have only been at it for 17 years.

Also, consider the fact that most of the plecos I breed all come from the Big Bend of the Rio Xingu and that most are only found there and nowhere else. This raised the odds that a lot of the fish could be related to some extent. But lets not forget good old mother nature here. She does her best to insure the continuation of species and to insure there are ways to try to avoid inbreeding. In my groups, only the top males and females spawn. There is a lot of fighting that goes on to insure this is the case. Mother nature works to insure the strongest offspring are what will result from any spawning.

When we pair up fish, we interfere with the natural way things would work in the wild. I have been fascinated by the various means fish use to spawn and wanted to see as much of it as I could. It is why I settled on the more expensive and rarer plecos with which to work. Fewer offspring which sell for a lot more than most fish means less works, less space needed to for growing out. I was always space constrained so it was the perfect way to go in my case.

Some of my fish were so rare just amassing a group was difficult. Then add that Brazil created the permitted lists and a lot of fish became illegal to remove from the country. So sometimes genetic diversity can be a challenge to come by. And sometimes there are species in the hobby which only exist in the tanks of hobbyists across the globe. If not for fish keepers who intentionally sought to keep such species alive on the planet if not in the wild, these species would no longer exist.

For a number of years I worked with a friend who imported fish and sold them from her home. It was an 8+ hour round trip for her to come to the trans-shipper in NYC to pick up her order on Sunday early afternoon. I wanted to be able to get wild fish i ported or farmed from good sources. So I worked with her. I could piggy back her order to get fish for myself very cheaply. I would drive 45 minutes to the trans shipper, pay for the order and then drive 2 hours to meet my friend. This cut her round trip in half. It also gave me access to cheap healthy fish. Healthy because my friend worked for a few years learning which sellers had the best option for any given species.

When I would be at the transhippers I would see trucks or other pick-ups being done by some well known pet chain stores. The difference between what I was picking up and they were picking up is they went for cheap and for a lot of less pricey fish typically seen in the average store. When I wanted rummy nose tetras I would get 50 and they were priced well under $1. I did not lose many fish I got this way as my friend knew exactly when to buy what from whom to make this the case. The chain shops were much less fussy and often bought mixed bags of species at the cheapest pricing.

There are no guarantees when it comes to buying fish. However, if you can find responsible and respected breeders, this is one way to increase the odds in your favor. Most of us take pride in what we do and go to great lengths to insure we sell healthy fish. I am almost as happy to hear a buyer has bred the fish I sold them as I am to find a new spawn in one of my tanks. Both ways I do the happy fish dance.

 

[emeraldking]

Generally if you buy fish from a shop or breeder they will be related (probably brother and sister). If you get wild caught fish, they could be related but much less likely than anything from a fish farm, which supplies shops.

Exactly! And thinking that you'll solve the problem by just buying specimens at other stores, is not always the best choice either. For if they have the same supplier, those fish could still be related. If I plan to buy the same kind of fish at different stores, I always ask which supplier they'll use. Stores in my area will tell me which provider they have for they know that I know all the Dutch wholesalers. And I also know a fair number of breeding farms which supply those wholesalers. To most lfs's I'm not the most easy customer there is.

 

[Colin_T]

Exactly! And thinking that you'll solve the problem by just buying specimens at other stores, is not always the best choice either. For if they have the same supplier, those fish could still be related. If I plan to buy the same kind of fish at different stores, I always ask which supplier they'll use. Stores in my area will tell me which provider they have for they know that I know all the Dutch wholesalers. And I also know a fair number of breeding farms which supply those wholesalers. To most lfs's I'm not the most easy customer there is.

I reckon you would be a great customer. You know what you want and you get straight to the point.

 

[Magnum Man]

Part of the problem with the hobby, as I see it, with breeding… is breeding should always be thought of originally, not something that comes up later… with many species where the hobby expects that you will buy 8 - 10 shoalling fish, those are the most likely to be related, and adding an additional school later from a different supplier, is often beyond most “hobbyists” so, we can assume most fish bred by hobbyists, are not as diverse genetically as they should be, to breed later…

However, there seems to be a good amount of genetic material available in several 100 eggs, that we don’t often see a 3 legged cat so to speak, from most home bred fish???

 

[GaryE]

I'll wager there aren't many farmers who run down to the cow store for a bag of calves when their adults die. But in the fish trade, very few people breed their fish beyond the occasional one generation experiment. Inbreeding isn't a problem when there is no breeding to begin with, and this is a consumer hobby now.

When breeding was popular, a lot of breeders kept studbooks and documented their sources. There were conservation groups exchanging fish to keep inbreeding at bay.

Even in this motivated group here on the forum, very few people keep any fish to the 3rd generation at home.

I've only been hit with it once, with some goodeid Zoogoneticus tequila. I kept them for quite a few generations, and at one point, my line became infertile and I had to let them die out. On the flp side, I have a killie I've bred since 1992 that is going great, after starting from one pair. Not many people get interested in projects like that, and we avoid problems by consuming from massive farms. When things go wrong there,species drop off the lists and we barely notice.

 

[Endlersendlers]

Lakeway Tilapia sells breeding groups that are unrelated. They have a process for tracking their breeding lines to ensure this and then they put potential groups together to observe and screen them for positive breeding behaviors, no alpha females to ruin the mood, etc. If the dynamics aren’t right they switch them out until they have a proper mating group.

If you don’t order a breeding group, you get one brood, all from the same parents.

 

[Colin_T]

I've only been hit with it once, with some goodeid Zoogoneticus tequila. I kept them for quite a few generations, and at one point, my line became infertile and I had to let them die out. On the flp side, I have a killie I've bred since 1992 that is going great, after starting from one pair. Not many people get interested in projects like that, and we avoid problems by consuming from massive farms. When things go wrong there,species drop off the lists and we barely notice.

Killifish seem to be able to tolerate inbreeding much better than most species. It's believed to be an evolutionary trait caused by them living in small isolated areas where they don't often get new bloodlines coming in.

On the other hand, a number of Australian rainbowfish in the tropicas are regularly exposed to new bloodlines and that may come from a different species. This happens in the wild when the local waterways flood and a fish might get washed into another river or creek. It then joins a group of rainbowfish from that creek and breeds with them. One of the guys in ANGFA got some Melanotaenia trifasciata from Cape York in Queensland many years ago. He has photos of them and got some new ones from the same river more recently. They were different colours. DNA testing showed the new fish had DNA from several species of rainbowfish. These are natural hybrids caused by cyclones washing fish from one river into the next.

Rainbowfish bred in captivity regularly show genetic deformities after only 1 or 2 generations of captive breeding.

 

[GaryE]

I like to think hobbyists will get back on track with breeding responsibly, but first they'd need to breed fish, and they don't. So I'm not holding my breath.

I know of half a dozen good rainbow breeders within 25 hours of me (none closer than 10) so the exchange of genetic material is unlikely. The big destroyer of hobby bows here is TB though. We just consistently lose fish, and because of the disease issues, I have reduced my rainbows to only the healthy ones I have - boesemani and wanamensis. Since I can't do exchanges, I know I'm running the lines into the ground. Eventually, inbreeding will win.

With Cichlids, I know one breeder who keeps species across multiple generations. Space is always the issue there, as territoriality makes long term breeding of safe sized groups a real problem. My friend in Europe has built a network with other breeders locally, and they share the riches. That keeps them going.

There never was a golden age in aquariums, and what we look back on were baby steps that could have developed but clearly didn't. Groups like AGFA are important, and I wish we had them for all fish. We don't.

So yes,inbreeding will be an issue where it isn't already one now, and we're doing nothing about it. We keep fish like stamp collectors used to keep stamps, only fish are perishable. In 50 years, I highly doubt there will be an aquarium hobby. We'll enjoy learning while we can.

 

[Colin_T]

Fortunately with rainbowfish, they can live a long time (assuming they don't have TB) and they keep breeding their entire lives. Gerald Allen got rid of his fish some years ago and one of the guys (Ken) in ANGFA got them. One tank had 1 male and 2 female Melanotaenia eachamensis - Dirran Creek in. The fish were wild caught and they about 9 years old. The male had cataracts and could barely see but he could still display and breed with the females.

So unlike killifish where you start a new generation each year because they age so quickly, with rainbows you can start a new generation after 5-10 years if you need to.

You need to breed Glossolepis wanamensis because they are close to extinction in the wild or they are extinct (whichever one it is) due to the tilapia that were released into the lake where they occur.

 

[BigJfish12]

I've been told the genetics of livebearers are very weak due to inbreeding especially in guppies. So would buying guppies that are of colour variations mean they aren't related and produce fry with stronger genetics reducing the chances of fry with deformities?

 

[Colin_T]

I've been told the genetics of livebearers are very weak due to inbreeding especially in guppies. So would buying guppies that are of colour variations mean they aren't related and produce fry with stronger genetics reducing the chances of fry with deformities?

Guppies that are different colours are less likely to be related. However, they might have some common ancestors going back 10-20 years. But you should get healthier guppies if you breed different colours rather than the red with red or whatever is being sold in the shop tank.

 

[GaryE]

It's really hard to put a finger on what's wrong with many of our favourite aquarium fish. Neons, guppies - they've gone from being as tough as cockroaches to being very fragile purchases. Is it inbreeding? Is it chronic disease and the consequences of mass production? Is it a series of passing viruses, as almost destroyed hobby stocks of angelfish and dwarf gouramis in the past?

For quite some time before Iridovirus was identified as the gourami killer, I read people digging in and swearing it could only be inbreeding. We have to make educated guesses, and while you can send a guess to school, it's still a guess.

Outbreeding is a danger too. @Colin_T pointed out my wanamensis are possibly extinct. I've spent years spreading them out as best I could because of that. But I bought some from a rainbow expert in 1990 or so, bred them and moved on. When I wanted them again, it took me 20 years plus to find them. I bought a few things sold as wanamensis, but as they grew out, I realized they were hybrids off the careless farms, and not the natural species. Hybridization is going to make a lot of endangered fish extinct in the hobby, as it already has. I was lucky to connect with a rainbow freak who had the real thing. But there are very few rainbow enthusiasts in my country, and hybrids replace natural species in stores on a regular basis.