Updated: Apr 9, 2019
Somethings up. Your angelfish are acting weird. Are they sick? Do they need a water change? Or did your little angelfish grow up and realize they want to start a family of their own? Angelfish breeding is both a lot of fun and very rewarding, with large adults laying close to 500 eggs, but you need to know what to watch for as your fish start to pair off so you can be prepared for what comes next. Here are the top signs that your angelfish are preparing to #breed.
Angelfish are "generally" peaceful
Angelfish are outgoing fish that like to hang out in the bottom half of your aquarium. They're inquisitive, not prone to fright, and just like to chill and check things out that catch their eye, whether it's their tankmates, a snail, or you. Would you believe it's been proven that angelfish can tell time? That's why they're always waiting for you when you walk into the room to feed them. Angelfish are creatures of habit, and when those change, something is definitely off. I'm assuming that you've ruled out any visible diseases and you have adult pterophyllum scalare, not altums or leopoldi.
Check your other angelfish
Angelfish are #schooling fish as babies, with an ever-increasing personal space as they age. As adults, they may not school tightly, but when one fish heads to one side of the aquarium, the others follow. They seem to want to revolve around each other without getting too close (about 3"). If you have a breeding pair, your other angelfish will pick up on this immediately and they'll hide as tightly packed into a corner as possible. They're not sick, they're scared. Their former friends just turned into executioners. This is your most obvious sign, and it's what I look out for every time when growing angelfish for breeding.
Your fish will have coloured up to their full potential. The vertical stripes of silver angelfish will go jet black, and you'll notice their cheek colouration darkening as well. In the gallery on the left is the same male angelfish with the photos taken as he was preparing to breed. Your koi angelfish will become more vibrant, with their gold spots potentially becoming more orange. This is a little more difficult to spot in the ornamental strains, like gold or albinos or the other variety of colours angelfish come in, but you'll start to notice they're flaring their fins more, and flicking them when other angels look their way. Fin flicking seems to be their initial "Back off, bro" warning to each other. They'll swim around in full display of their colours, 24/7.
#Freshwaterangelfish lay their eggs on vertical or near vertical surfaces. Breeding cones, slate rock, filter intakes, heaters, and even the aquarium glass itself can provide a spawning substrate for them. You'll notice that they're starting to peck at these surfaces, testing different areas out to see if they are suitable for their eggs. Angelfish DO NOT lay eggs on the #substrate of your aquarium. Ever. If they are pecking at the gravel they are searching for food, not picking a breeding site. In the video below you'll see the level of intensity that angelfish use to clean their chosen site. This is just them testing it out. They'll do this for as long as it takes for them to feel like the site is ready, and angelfish typically start doing this within 48 hours of being ready to breed.
It's all about real estate
Here's where things get fun. Your four foot 90 gallon aquarium suddenly becomes a really small fish bowl in the eyes of your angelfish. I've had pairs claim 2/3 of a 90 gallon tank for themselves, while not allowing the other angelfish out of the top corner of the aquarium. You angels will claim as much space as they can defend for themselves. This causes a lot of #stress for your other angelfish, so it's a good idea to move them into another aquarium or move the breeders. Caution though, if you move the breeders you can disrupt their process and delay them laying eggs.
#Pecking and #nipping are a normal part of angelfish behavior, but when they are getting ready to breed, it escalates. You'll find body blows become a lot more common, and you'll see some interesting angelfish communication taking place. When an angelfish is challenging another, it flares its gill covers near its chin. If the other angelfish wants to back down, it will raise its chin as a sign of submission. When #breeding is imminent, #aggression escalates even farther from there. Your adorable (not so little anymore) angelfish become flashing darts of death. It doesn't matter what the species is, all of their tank mates are a target. The breeding pair, usually the male, will rotate onto his side, and attack at full speed. The female is too preoccupied with the final preparation of the breeding site, but if any fish gets too close for her liking, she'll do the same darting attacks. In the below video, you'll see two pairs of breeders facing off. They do this all day, every day. The drive to protect their eggs is all consuming.
Know your fish
Angelfish will start to exhibit all of these behaviors as they prepare to lay eggs. An aquarium environment is not a natural environment for fish, and you'll need to prepare in advance so that the rest of your fish are not at risk of being killed by the protective parents. By noticing and responding to these signs, both you and your fish can enjoy making little angelfish fry.
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.