Attempting To Breed Praecox Rainbow Fish. Does Inbreeding Exist In Fish? Is This The Correct Way?

I have kept fish for a long time but have never attempted to breed before. I am planning on attempting to breed my dwarf neon rainbow fish and currently have a spawning mop in the tank in the hope that I will collect some eggs.

My first question is:
I bought all the fish at the same time from the same shop. For this reason, I'm assuming there's a good chance they could all be brothers and sisters. Will this have a negative impact on their offspring?

When I begin to see eggs on the spawning mop, I intend on putting the mop into a plastic container and floating it in the tank with the lid on. Changing part of the water every other day. This is a method that I found on youtube that claimed to be the Gary Lange method. When they hatch, I will move them to a small tank with a sponge filter.

Does this sound like I'm doing it properly?

Thanks.

 

I went thru trying to breed Praecox and M Trifasciata. I followed the GL method and picking the eggs and changing the water every day is very time consuming. I only had 11 survive from my Praecox project. I got over 50 from my M Trifasciatas.

I put a breeding pair in a 20 gallon long with a ball of moss about 6-8" in diameter to one side. I fed the pair frozen blood worms to condition them. I pulled the pair 2 weeks after I first saw some eggs in the moss. They will eat some of the eggs and some will fungus but there will be a ton more in the moss as they will keep spawning in the moss. After a week or so, I started seeing fry in the empty tank.

This is where I tested a theory I had. I collected about half into a 2L tupperware container to float in the tank and left the other half in the tank. Almost all the fry in the tank disappeared (kinda like what happened to the Praecox fry) but almost all the ones in the container survived.

The fry are tiny. The first couple of weeks, I fed them infusoria and 5-50 micron Golden Pearls. They grow very slowly. Keep the temps at 80-82°F.

 

That sounds amazing. How do you get the Tupperware container to float? Do you put a lid on it with air still in there or would this starve the water of oxygen?

I’ve 4 male Praecox rainbows and 8 female rainbows in a tank trying to collect eggs from. However, there’s a female Krib in with them. Not sure if shel eat the eggs before I get to remove the mop.

 

The container has no holes. The fry are fine in the container for a couple of months. I ran an airline going at about 2-3 bubblles per second. No lid.

The krib will definitely eat the eggs. The Praecox will eat the eggs too if it can. If you're going to collect them, mid-morning is the best time as they'll usually spawn at dawn.

 

If I was to hatch the eggs through floating a Tupperware box in the tank, would it be safe to do this with the lid on the Tupperware box? I'm not sure how else the box would float. I would be taking the lid off at least once a day to feed them and change the water anyway. I'm not sure how else I would maintain a consistent decent temperature in the box without floating it, as nights get cold in the UK.

Also, will it be possible to gather eggs from the spawning mop as there is a krib in the tank or am I wasting my time trying?

 

I used a plastic Ziploc container (not tupperware but almost the same). If you don't fill the container to the top, it will float. I had the water level in my tank high and the container had just enough water to float and touch the glass lid so it wouldn't tip over.

These are what I've been using for the M Trifasciatas.
https://ziploc.com/en/Products/Containers/Rectangle/Containers-Large-Rectangle

This is an older pic using whatever containers I had before buying the Ziplocs specifically for raising fry. The water level was lower for the container on the left.



You need to feed your fry at least twice a day or they will die off. I fed mine 3-6 times per day. You will need infusoria or Golden Pearls 5-50 micron or they will starve and die off. Any other food is too big so make sure you have food for them.

There will be eggs deep in the spawning mop if it's thick but not as many as you would w/o a krib in the tank. The Praecox will also eat some eggs.




Pulling eggs is tedious work. It took me hours to pull 50-100 eggs and separate them. If you have a spare tank, I would put moss and/or a spawning mop and drop the breeding pair or group in for 2 weeks and pull them and let the eggs hatch naturally. Scoop up the fry you see swimming near the surface and raise them in a container until they're at least 1/2" (3 months).

The white spots are rainbow fry. They're about 2 weeks old. I left them in a 20 gallon tall and most died off because they couldn't find food. That's why the container worked for me.



M Trifasciata fry. Newly hatched on the left, about 2 months old on the right (only 4)



A couple of weeks old



20g long with breeding pair

 

Thanks for the advice. Will definitely be trying this over the next few weeks.

As for food, would this stuff be suitable for the first few weeks/months?



I've searched for golden pearls before and I don't think it's available in the UK. Not that I'm aware of anyway.