Basic Groups of Fish

There are six main categories of fish that are not necessarily compatible:

1. Goldfish
2. Peaceful
3. Aggressive
4. Semi-Aggressive
5. Brackish
6. Saltwater

Goldfish

Goldfish have a category of their own because they are unpredictable. Generally they will nip on fan tailed Goldfish or other slow moving tail fish, which is why it is best to keep them by themselves. They do not have problems with Coi (Carp) fish.

Eat flake and pellet food.

Peaceful

Tropical fish are almost all peaceful and compatible with each other. A couple of these are; Tetras, Mollies, Platties, Swordtails, and a couple others.

Some of these have specific food that must be fed, mostly pellet food.

Aggressive

Barbs are mostly aggressive, but there are exceptions to a couple of them. Angelfish are generally peaceful but extremely aggressive during spawning which is why they fall under this category. This category is for aggressive fish that are a bit aggressive but not to the extent the Semi-Aggressive fish are.

Eat flake food, pellets, worms, and can sometimes nibble at dead fish.

Semi-Aggressive

Includes; Arowanas, Bala Sharks (a type of barb), Silver Dollars, Oscars, Cichlids, and a couple others. Even with this category, you have to watch which you put together. When you put them together it is always best to rearrange your tank scenery so the fish will be too busy exploring rather than focusing their anger on the newcomers. Also, it is necessary to keep their size as close to the rest as possible, because the smallest fish will get picked on, in case of Cichlids.

These fish can get fed pellet food, some of them can get flakes and others it is best to feed them feeder goldfish (come in two sizes) or live worms (frozen worms work too).

Brackish

Brackish are fish that generally require salt in the water. If belly start to turn black on brackish water puffers, add salt and they should be fine in a couple of says.

Most of these are aggressive, some can survive in fresh water, but it is best not to test them. Other fish can survive in brackish water; little salt cannot hurt fish, but too much can.

Eat worms and pellets.

Saltwater

In saltwater there are two categories:

1. Aggressive
2. Non-Aggressive

See a fish store for details. There is too much to write about these because there are so many kinds of fish and each may have its own requirements. Saltwater is expensive to set up and maintain.