I need some help breeding my danios. I have 6 of them in a tank. I was wondering how i could breed them?
Thankfully, Danios are one of the easiest egg laying fish to breed.
One of the things you need to know is about raising the fry. Danio fry are small when they become free swimming so you will need to start culturing infusoria for the babies. I suggest you either search "infusoria" on this site or Google it to get a good understanding of what it takes. It's not difficult to do and truthfully, I never really had much success raising any quantity of fry (even with the commercial "first foods") until I started using infusoria.
As for preparing the fish to spawn, the best results come from separating the sexes for about a week to 10 days and feeding them high quality protein foods added to their regular diet to help condition the breeders. This is best done in separate tanks and not just using a divider because when the fish are ready to breed, they send out a hormone alerting the mate that they are ready and this can be sensed when they are sharing the same water. Separate tanks are best to prevent premature egg release.
The spawning tank: there are a couple of different methods being used to spawn danios so I will give you both. I've only used #1 (with great success) but believe success can be achieved with the second.
#1- I've used everything from a 10 gal tank to a 6 or 8 compartment Betta tank to spawn Zebras. I use a bare tank with just a submersible heater and an airline with an airstone for oxygenation and new water with an adjusted PH of 7.0 (neutral). The bottom has a layer of marbles as the substrate so that when the fish spawn, the eggs will fall between the marbles and the parents can't get to them to eat them (which they will do.) The water level should be about 2 inches above the marbles. The tank is heated to 78 -80 degrees and the airflow should be steady but not too high. (The breeders will be in this tank for a short number of days so cycling the aquarium is not necessary.)
Once the fish have been conditioned, you'll want to put 2 males for every female into the breeding tank. Depending on how large the breeding tank is, you can put multiple trios in the same tank. Since the fish have been separated, the urgency to breed is usually high and you should see spawning within 24-48 hours. You'll know for sure if they spawned when the females no longer are plump with eggs or you see small clear globes (the eggs) in between the marbles. (I used to set up my breeding tank on a rack so that I could see up from underneath the tank to check for the eggs.) If no spawning has occured in 2 days, you can replace up to 5% of the water volume with a cooler temperate water to help stimulate the fish to spawn. Make sure this water has a ph of neutral to slightly acidic value. Once spawning has occured, you will remove the breeders from the tank and replace them back into their conditioning tanks if you plan on breeding them again or your main tank if you just want them for your tank. Once the fry become free swimming, you'll want to replace the airstone with a cycled sponge filter for the remainder of their time in the spawning/hatching tank.
Method #2: In a bare tank, you'll need to make a breeding trap using a glass tray with a plastic lid. You will cut out a good portion of the lid and replace the plastic with a mesh (either netting or wire) that is big enough to let the eggs fall through but not big enough to allow the parents to get through. Over the mesh you will put some strings of live plants like anacaris or any other plant that is not too thick to allow the eggs to fall through for the fish to breed on. You'll use the plants sparingly so that the eggs will fall off the plants and into the glass tray. You'll follow the same procedure regarding conditioning the breeders but the water height will not matter. The fish will spawn only over the plants making repeated trips so in theory, the eggs should not be lost.
The eggs should hatch in about 24-36 hours but the fry will not become free swimming for about another week. (While you are waiting for the for the fry to reach this stage you should be setting up your infusoria cultures.) Approx. 30 days after they are free swimming and eating the infusoria, the fry should be large enough that you will need to move them to a larger tank to grow out and you should be able to feed them live or frozen baby brine shrimp or other powdered fry foods.
Sexing the fish: Females are generally larger and more rounded than males so when you are picking out your breeders, try to get ones that already have eggs. An egg laden female will look different than a slimlined, healthy male. Pick enough fish to have 2 males to every female. Egg count is anywhere from 100-300 eggs per spawn depending on the size and age of the female.
Hope this helps.