Updated: Apr 9, 2019
You've grown your prized angelfish, they've paired up, and you watched with joy and amazement as they laid their first clutch of #eggs. You've put the eggs in their own 10 gallon tank away from the parents....now what do you do? The internet is a great, and terrible, source of conflicting information. Believe me when I say I've read it all, and tried it all. Here's what I learned, and what you need to know to enjoy a 90%+ #hatchrate.
Water conditions matter...sort of
You've probably read that nitrates must be 0, water must be acidic, and for some reason you need to play classical music at 22db. It's all BS. I've experimented and put angelfish eggs in "dirty" water, I've put them in tank water that was not their own. I've even overmedicated (3x dose) just to see what would happen.
Use aged water
I've tried using the original aquarium's water, aged water, and water from an assortment of my aquariums. I found no impact on hatch rate. I ensure any water I use is aged 48 hours to remove chlorine and compressed gasses. If your city uses chloramine, you'll also need to add a conditioner to remove it. For under $15 you can get a great container from Home Depot that you can use for this purpose.
Water temperature matters
Fish are cold blooded and dependent on water temperature. You want to keep the eggs at 82-84F. This will hatch the fry within 48 hours of the eggs being laid. If you drop below 80F, then the eggs take approx. 12 additional hours to hatch. This allows more time for fungus to attack the eggs, lowering your hatch rate.
Use a mature, large sponge filter
You don't want the tank cycling as your fish are hatching. Make sure that you have a #spongefilter that's been in a cycled aquarium for 3-7 days (3 days in an emergency, 7 preferred). I put my fry in 10 gallon aquariums, with the large sponge filters rated for 60 gallon aquariums. There's going to be a large bioload as the fish start to grow, and the smaller sponge filters can't keep up. They only cost $2-$3 more and are worth it.
Fight the fungus
Use methylene blue. I've found nothing that works better. A full dose on the first day, and here's a secret, a half dose on the second day. It's a game changer. For those people that want to "raise their eggs naturally" and don't use medication, well, you're a fool. You are raising fish that have been selectively bred for a century in an environment that is nothing like their natural habitat, in water conditions that are far from pristine, on the best of days. Give the eggs a boost to stave off fungus and the little fry will love you for it.
Remove fungused eggs
If you get a bad batch, this part sucks. It's time intensive and your hand is going to cramp. Go buy a needle and a eye dropper. Use the needle to nock off the #fungusedeggs, and the eye dropped to suck them out. I don't like fungused eggs touching good eggs, and I've had mixed results with leaving the dead eggs in the batch or removing them. They're fungused. Get them out.
Do not water change the aquarium
GASP! This goes against everything on the internet!!! Ten+ batches of eggs a week for a few years now has taught me to experiment. I don't water change the aquarium for about 10 days from when I put the angelfish eggs in. It's not a hard and fast rule, I might go a few days longer, but I rarely go less than this. Your eggs are creating very little bio-load. Nitrates are not piling up. Your filter is mature and doing it's job. Leave sleeping dogs lie. As for the 10 day mark, I'll do a 15-20% water change a few days after the fry have started swimming, then put them into our regular water change cycle (50% every third day). The only reason they're on this cycle is because this is my regular schedule for all my tanks, and I don't want to forget them or create work on off days. I've had fry tanks that I only water change weekly because I was testing water conditions daily and they were within safe range (we've found this to be under 50ppm nitrate).
Add some air
Ensure that you have #waterflow over the eggs by adding an air stone that won't move after you've placed it. Those tiny air stones are cute, but good luck keeping them in place. A nice, gentle stream of air will push water over the eggs for the next 48 hours, helping to keep them clean. A quiet air pump is highly recommended.
Try your best, you will succeed
These are some of the most important tips I've learned to turn your #angelfisheggs into #wigglers, and I hope that you have all the success in the world. Sometimes though, the eggs just die. It's not your fault. Inexperienced angelfish parents may not have mated properly. The male may have been gotten distracted and forgot to fertlize a large section of eggs. The genetics of your fish may be too skewed for the eggs to be viable. There's a lot of factors out of your control, but mark down what you did, and in a week to 10 days, you're going to have the chance to try again!
Leave a comment, a question, or even a contradiction down below and we can learn together.
Andrei Vexler is an aquarist with over 20 years in the fish hobby. Having run a fish room with over 700 freshwater and saltwater aquariums, Andrei found his passion in South American cichlids, particularly altum angelfish. Growing and wholesaling angels to the GTA and surrounding area, he shares his years of experience in his blog for advanced aquarists.