Fish Compatibility Groups|
written by Dave Burr and Thuong Pham
To view fish compatibility chart,
The following are guidelines for choosing your group of fish. However, remember all fish have individual personalities, and there may be exceptions to the rules.
Please read about each individual fish in our fish section before purchasing
to make educated decisions. We cannot guarantee fish behavior.
- Predatory Fish-Only Tanks - The following fish can be housed together in a predatory tank, but please also read our
general guidelines below.
- predatory wrasses
- large angels
- large tangs
- large butterflies
- There are two types of predators:
- Nippers - These predators (such as triggers) nip at their prey
bite by bite until dead. Prey size does not matter.
- All-in-one gulpers - These predators (such as groupers, lions,
and anglers) will only eat prey they can take in one gulp. If the prey
is not small enough to swallow whole, they're not interested.
- Peaceful Reef Tank - The following fish can be housed together in a peaceful reef tank, but please read our
general guidelines below.
- green chromis
- pygmy angels
- small tangs of different shapes
- small reef-safe wrasses
- damsels - but beware as they often become aggressive
- General Guidelines for Adding Fishes:
- Be careful when housing fish of the same size, shape, and/or colors
together, especially if they are from the same genus.
- Some fish are okay to pair or school if
we explicitly state it under our individual
Read fish descriptions carefully as some
fish such as clowns must be added at the
- Mix angels from different regions. For example, an angel from the Red Sea can
usually be kept with an
angel from the Indo-Pacific.
- Add more aggressive fish last. Allow peaceful fish to set territories first.
- Any time you are concerned two fish may fight, add them at the same time so they can establish separate territories. If you add one first and then
the other, the whole tank becomes the first fish's territory - not good.
- When adding more than one fish, add one pair or add in odd numbers. (2, 3, 5, etc. - Not 4, 6, 8, etc.)
How can I stop my fish from fighting?
- Sometimes rearranging some of the rock in your aquarium will
prevent squabbles by creating new territories and breaking up
old “established” territories.
- Create new hiding places using the rocks.
- Make sure your fish are well fed. Fat predators are not as
likely to harass their tank-mates.
What should I do if certain fish will
not stop fighting?
- At this point you must remove the aggressive fish from your
- If you have trouble catching them try dropping some of their
favorite food on the surface and catch them quickly with a net
when they come up to eat it.
- If you still can’t catch them try using a trap.
How do I know a fish will not eat my
coral and invertebrates?
- You can never be 100% sure about the compatibility of your
new fish until you release it into your aquarium and watch its
- What you can do is educate yourself, make educated selections,
and hope for the best. It is what all hobbyists must do.
- Please note: Most fish that eat coral have
only a few selected types of coral that they will eat and will
not bother other corals. Read about the fish and corals on our
website for more specific details about compatibility.
- With corals, it is easy to remove them and trade with a friend.