If you’re keeping more than 2 angelfish, a good rule of thumb is to add 10 gallons after the first pair for each fish. So, you start at 30 gallons (110 L) for 2 angelfish. Then, you’d need a minimum of 40 gallons (150 L) for 3, 50 gallons (190 L) for 4, etc. [2] X Research source You can keep anywhere from 2-6 angelfish together in the same tank. If you only have 1 angelfish, at least keep other fish species in the tank—angelfish should never be entirely alone. [3] X Research source The taller the tank, the better. Angelfish are bottom swimmers, but they enjoy swimming vertical channels as well. It’s also harder for an angelfish to defend a big territory if their tank is very vertical, too. This makes taller tanks ideal for minimizing aggression.
Angelfish require a mixed diet of commercial fish flakes or pellets, and frozen/dehydrated arthropods, like shrimp or mosquito larvae. If angelfish don’t get a healthy mix of food, they may become aggressive. [5] X Research source Feed your angelfish twice a day at the same time you feed their tankmates. In terms of the amount of food, it depends on how many fish you keep in the tank. Your angelfish should never take more than 2 minutes to finish their food, though. If you feed them and it takes them more than 1 minute but less than 2 minutes to eat, you’re giving them enough food. [6] X Research source
An angelfish may chase off other fish who wander into their territory, but they should stop pursuing them once they run away and hide.
Don’t worry if your angelfish doesn’t take to the hiding spot right away. It can take some angelfish a while to get used to new features in their territory. Hiding is a natural behavior for angelfish. However, if your angelfish is hiding for extended periods of time, it might be a sign that your water quality is off and your angelfish is sick. If the fish is sick change the water and add aquarium salt. [9] X Research source It is the least harmful to fish and is effective in treating infections. [10] X Research source
You can change the temperature of the water by adjusting the dial on your aquarium’s water heater. Test your tank’s water using pH testing strips or a digital probe. If the tank’s pH level is too low, change the water out or add rocks and shells to slowly increase the pH. If the tank’s pH is too high, add driftwood or peat moss to naturally lower the pH in a sustainable way.
Water changing can be a bit of an art when it comes to angelfish. Every school has their own distinct leaders, personalities, and hierarchies. It may take a bit of trial and error to figure out how much water you should cycle out and how often you should do it. When you buy new fishes do not put bag water into the aquarium. [13] X Research source
This is the kind of thing you don’t want to too often. Totally cycling the water can be stressful for your fish.
If you’re new to angelfish or you haven’t set an aquarium up yet, stick exclusively with female angelfish. A school of female angelfish won’t fight or bully one another normally.
Neon tetras in particular are natural food for angelfish. Other edible fish for an angelfish include rasboras and guppies. The one exception here is swordtails. Swordtails are tiny fish, but they’re just aggressive enough to put an angelfish in their place. In fact, they can even keep an angelfish from getting too aggressive.
Other species that will do well alongside angelfish include catfish, plecos, and loaches. [18] X Research source If the angelfish is the smallest species in the tank, you’ve probably got a good tank composition going. Barbed fish and fin-nippers are no good alongside angelfish.
So long as nobody is losing any fins and the fish aren’t leaving marks on one another, don’t worry. Your fish will be fine. Normal angelfish combat should look a bit like dancing. They’ll face their opponent, swim back and forth rapidly to beat them with tail, and try “kissing” their opponent (biting them lightly). So long as they aren’t pursuing their opponents perpetually after they back down, it’s not a big deal.
You might see some slightly aggressive behavior from the male angelfish after mating has taken place. Angelfish will usually eat their eggs in captivity unless you separate the breeding pair from tankmates and slightly overfeed them. [21] X Research source If two angelfish fight a little bit after fertilizing eggs, they’re probably competing over the food the eggs represent.
