Fry and Inbreeding

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michmich

Aquarium Advice Apprentice
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Oct 15, 2022
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The guppy fry in the 10 gallon tank are doing great so far! :) Speaking of inbreeding, if I keep some of the fry, wouldn't they mate with each other? Is this considered inbreeding in the fish world and if so, at what point would I need to separate the sexes?
 
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If the baby fish grow up and breed with each other, they will be inbreeding and it is bad for fish, just like any other animal. You get bad genes mixed with bad genes and really bad babies. Guppies are already badly inbred and you don't want to make them worse than they already are.

You separate the babies as soon as you can sex them. Look at the anal fin and when it becomes long and thin and no longer looks like a fan/ triangle, then move those out because they are young males. If you keep female young, you can let them grow up to a year old and then buy in an unrelated male to breed with them. Or if you only want colour, then keep the males and get rid of the females.
 
To add to Colin_T's remarks, inbreeding is the way many fish colors have been created and solidified so all inbreeding is not bad per say. Haphazard inbreeding is what usually creates fish with genetic deformities or poor health. Line breeding ( a method that uses the breeding of parents to children and brothers to sisters, etc) helps to create a desired outcome.
As mentioned, Guppies have come a long way from the origins and the chances of getting " quality" fish from them today is slim. You may still get some interesting colors from a haphazard pairing tho but that in no way guarantees that you can duplicate that result continuously.
If you follow the advice of separating the sexes, you should find that the males will color up much more intensely with no females around. They use color as an attractor for females so they will be in competition with each other to get the best colors. That works out good for you. (y)

With the females, the older and larger they are, the more and larger young they can produce so keeping the females virgins for at least a year works to your benefit as well.

Hope this add on helps. (y)
 
Thank you, yes, this is extremely helpful! Because the birth of these fish was a complete surprise, I've had to go out and get another tank which is currently cycling.

Could you advise me on a timeline? I definitely want to separate the sexes and will likely be giving away some of the fish to friends. I'm not sure what to do with the ones that I can't give away, but I might ask at my reputable fish store what they advise.

The first batch of fry only had 2 survivors and they are now a month old. The 2nd batch is just 5 days old and there are many more of them. How long before they reach sexual maturity?

I have added a sponge from another tank to speed up the cycling of my new tank, so hopefully it should be ready sooner rather than later.

The other question I have is whether a male only guppy tank is peaceful. I ended up having females only because of the harassment that would come from any male guppy I would add in with the females. It was relentless. If you have only males, do they coexist peacefully? More or less?
 
Thank you, yes, this is extremely helpful! Because the birth of these fish was a complete surprise, I've had to go out and get another tank which is currently cycling.

Could you advise me on a timeline? I definitely want to separate the sexes and will likely be giving away some of the fish to friends. I'm not sure what to do with the ones that I can't give away, but I might ask at my reputable fish store what they advise.

The first batch of fry only had 2 survivors and they are now a month old. The 2nd batch is just 5 days old and there are many more of them. How long before they reach sexual maturity?

I have added a sponge from another tank to speed up the cycling of my new tank, so hopefully it should be ready sooner rather than later.

The other question I have is whether a male only guppy tank is peaceful. I ended up having females only because of the harassment that would come from any male guppy I would add in with the females. It was relentless. If you have only males, do they coexist peacefully? More or less?
To answer the first part, timeline, it's hard to say. Males are capable to halt maturation of other immature males through hormones so it's going to be a look and see kind of thing. You'll see the early developments of the gonopodium so you will have time to separate them. It doesn't just happen overnight but within a few days.

A sponge filter from an existing tank should have a bacterial load in it that the new tank should not go through any kind of cycling period. ( The term " Cycling" is nothing more than the creating of the bacterial bed. In an established aquarium, the bacteria that's already there will grow on any well oxygenated surface. ) You just don't want to overload the new aquarium to stress the bed. Always do your ammonia tests when starting a new tank, even with an established filter.

Male Guppies will compete with each other. It's what makes their colors "shine". Will they kill each other? Not usually. You may see a ripped fin now and then but rarely a corpse. Males instinctively want to breed with females so it's not surprising that your females were getting " harassed". It's why most breeders sell trios ( 1 male-2 females) so that the other female gets some peace. Truth is, the females control conception so the males all have to try. She just doesn't have to accept. That's a behavior you cannot change.

Hope this helps. (y)
 
Could you advise me on a timeline? I definitely want to separate the sexes and will likely be giving away some of the fish to friends. I'm not sure what to do with the ones that I can't give away, but I might ask at my reputable fish store what they advise.

The first batch of fry only had 2 survivors and they are now a month old. The 2nd batch is just 5 days old and there are many more of them. How long before they reach sexual maturity?

Under ideal conditions, baby guppies can reach sexual maturity at 1.5 to 2 months of age. However, it usually takes a bit longer and comes down to how much food they get, water temperature, water changes and water volume.

Baby fish should be fed 3-5 times a day and given as much food as they can eat. After feeding they should have fat stomachs and look like a gravid (pregnant) guppy. Make sure you don't leave uneaten food in the tank to cause water quality problems.

The optimum water temperature for growing baby tropical fish is 28C.

You should do big (50-75%) water changes and gravel clean the substrate every day or every couple of days for maximum growth rates.

A larger container can help fry grow faster because there is more room for them, and any growth inhibiting hormones they release are diluted in the larger volume of water. However, you can grow up fish in small tanks and most of my rearing tanks were 2 foot long x 10 inches wide x 12 inches high. They contained between 20-50 baby fish and were fed 5 times a day. Got a 75% water change every day, and were kept at 28C. The fish in these tanks were sexually mature at 2-3 months of age. They were egg layers, (not livebearers) and take a bit longer to grow than guppies. But you can grow fish quickly if you feed them well and do big regular water changes.


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The other question I have is whether a male only guppy tank is peaceful. I ended up having females only because of the harassment that would come from any male guppy I would add in with the females. It was relentless. If you have only males, do they coexist peacefully? More or less?

If you have siblings, they usually get along better than unrelated males. However, not all siblings get along and sometimes adding two unrelated males produces a good group of friends. But as a general rule, male guppies should get along together once they work out their pecking order, which should only take a day or two. If two male guppies are constantly fighting and it's been going on for more than 3 or 4 days, separate them because they won't get along.

Male guppies can turn their eyes black when they are trying to intimidate other males. So if you see a guppy with a black eye, it's because he is having a barny with one of his tank mates.

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In the wild, female livebearers hang out in large groups consisting of between 20 & 50 (but sometimes up to 100 or more) females. These groups have a pecking order with the biggest most dominant female ruling the group and she has a group of girlfriends who back her up. All the other females live in the group but are lower down the pecking order.

The groups of females move around rivers and waterways looking for food and places to hang out. As the groups move around a few males follow the group and try to breed with any females. The groups of males have a pecking order too and the biggest male will bully his smaller mates.

In the confines of an aquarium, the males will constantly harass the females and try to breed with them. This puts undue stress on the females and if there are too many males constantly pestering the females, the females can get sick and die.

It is preferable to keep common livebearers (mollies, guppies, swordtails & platies) in single sex tanks (either male or female but not both sexes together). If you want a group of males and females then have 1 male and at least 6 females (preferably 10 or more females per male) so the harassment is spread out over more females.
 
The guppy story becomes more fascinating by the minute!! I always read that you need to have 2 - 3 females to one male, but my experience was that the male would harass one female absolutely mercilessly. It was brutal to watch, and it really stressed me out to observe it.

Your explanation of what guppies actually do in the wild explains why it doesn't work in an aquarium. The 10:1 ratio makes way more sense, and the single sex tanks make the most sense of all!

I'm glad I have some time to figure everything out before they reach sexual maturity. At the moment, I am doing big water changes anyway because of the praziquantel/levamisole treatments, so I will simply continue with that practice.

Thank you again for such fascinating information!
 
Pardon me for asking, I'm hoping to get some tips. How much inbreeding can guppies do? I'm new to taking care of guppies. I have 2 male Lyretails and I'm planning to buy and breed them with green moscow females to get my desired color. What do I need to do to get my desired results? Idk why but people here just tend to ignore and don't even know what Lyretail guppies are. A hobbyist sold them to me as chops and didn't even know what to call them. Also some people just leave the fry in a tub outside till they grow big enough before putting them in tanks and selling them. Are they ok without any aeration?? I'm planning on making an isolation cube for fry in my 15 gal, I just need to know how many babies they could possibly produce so I can decide how big of a cube I need to make.
 
You don't want to inbreed any fish (including guppies) if you can help it.

Moscow guppies are generally unrelated to lyretail guppies so crossing them together shouldn't be an issue. If you use 1 male lyretail to breed with the female Moscows, then you can use the second male to breed with any female babies that are produced. If you have a number of unrelated males, then you can keep using unrelated males to breed with the young females from each batch.

Before you breed the females with the males, you should leave the females for 6 months or so to use up any sperm packets they carry. Common livebearers like guppies, mollies, swordtails and platies can carry 6 or more sperm packets from breeding with different males. The females can choose when they want to use a sperm packet to fertilise the eggs. The remaining sperm packets remain inside the female and she can use them any time conditions are good. Good conditions means good water quality, lots of food, a nice warm temperature, and no predators. Because the females carry the developing eggs for about 4 weeks, females can give birth about once a month for 6 months or more (depending on how many sperm packets they have), without any males being present. Once they run out of sperm packets, that's when you breed the females with new males.

If you get young females from your babies, keep them away from all males for the first 12 months. This will allow them to grow to maturity and develop properly, and they will have less issues when they become gravid (pregnant) and when they give birth. If you don't want to wait 12 months for the females to become fully mature before breeding, at least let them get to 6 months of age before breeding them. The females need to be physically strong enough to withstand the rigors of childbirth (guppy birth).

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PONDS WITHOUT FILTERS
Most freshwater fish can live in ponds without aeration or filtration. However, they need lots of live plants and a large water volume otherwise there is a chance they will die from poor water quality or sudden changes in temperature. Some people have fish in small (50-100 litre/ 12-25 gallon) ponds and they do alright. But the smaller ponds will have much wider temperature fluctuations and you won't be able to keep as many fish in it. The smallest outdoor pond you want is around 4 feet in diameter x 2 feet high, and bigger is better. I like above ground aquaculture ponds that are 8-10 foot diameter x 4 feet high. However, you need space for this size pond.

Aeration from an air pump, water pump or water feature is recommended in any pond even if it doesn't have a filter. The aeration helps mix the water so it is a more even temperature throughout, and helps reduce low oxygen levels in hot weather, which can kill fish.

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HOW MANY BABIES
Female guppies can produce between 10 & 100+ young per batch and can produce a batch of fry every month. Bigger older females will usually have more babies but they might only give birth once every 2 months. Smaller younger females usually have smaller batches and give birth about once a month under good conditions.

Guppies don't normally eat their young if the adults are well fed and there are plenty of plants in the tank. A lot of people simply leave the babies with the mothers and remove nay baby males as soon as they can be identified. But if you have 10 females giving birth each month, you can end up with lots of babies.

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CULTURING FISH FOODS
The following link has information about breeding fish in general and culturing food for the babies. It might interest you.
https://www.aquariumadvice.com/forums/f82/back-to-basics-when-breeding-fish-380381.html#post3578561

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WORMS
Livebearers like guppies, mollies, swordtails & platies are regularly infected with gill flukes and intestinal worms. If you want to breed them, deworm the fish and treat them for gill flukes before you do anything else.

Intestinal worms like tapeworm and threadworms cause the fish to lose weight, continue eating and swimming normally, and do a stringy white poop. They don't always have these symptoms but most do. Fish can do this for months and not be too badly affected. In some cases, fish with a bad worm infestation will actually gain weight and get fat and look like a pregnant guppy. This is due to the huge number of worms inside the fish.

You can use Praziquantel to treat tapeworm and gill flukes. And use Levamisole to treat thread/ round worms. If you can't find these medications, look for Flubendazole, which treats both lots of worms.

In the UK look for:
eSHa gdex contains praziquantel that treats tapeworm and gill flukes.
eSHa-ndx contains levamisole and treats thread/ round worms.
NT Labs Anti-fluke and Wormer contains flubendazole.
Kusuri wormer plus (contains flubendazole) - sold mainly for discus, comes as a powder which is quite hard to dose in smaller tanks
Sera nematol (contains emamectin)

Remove carbon from filters before treatment and increase aeration/ surface turbulence to maximise oxygen levels in the water.

You treat the fish once a week for 4 weeks. The first treatment will kill any worms in the fish. The second, third and forth treatments kill any baby worms that hatch from eggs inside the fish's digestive tract.

Treat every fish tank in the house at the same time to prevent cross contamination.

You do a 75% water change and complete gravel clean 24-48 hours after treatment. Clean the filter 24 hours after treatment too.

Do not use the 2 medications together. If you want to treat both medications in a short space of time, use Praziquantel on day one. Do a 75% water change and gravel clean the substrate on day 2 & 3. Treat the tank with Levamisole on day 4 and do a 75% water change and gravel clean on day 5, 6 & 7 and then start with Praziquantel again on day 8.

The water changes will remove most of the medication so you don't overdose the fish the next time you treat them. The gravel cleaning will suck out any worms and eggs that have been expelled by the fish. Repeating the treatment for 3-4 doses at weekly intervals will kill any worms that hatch from eggs. At the end of the treatment you will have healthier fish.
 
Thanks I'm gonna review this all later. Good thing I asked around 1st cause there were 4 types of guppies that I had my eye on. Gonna stick with just 2 types for now
 
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