Saltwater aquariums are popular for their wide range of attractive fish and accessory options. In our last entry, we went over the 6 Big Rules for Choosing Saltwater Starter Fish. However, when selecting fish for your custom aquarium, a list of fish to include is only half the story. It’s just as important to know the types of fish to exclude.

Unlike freshwater aquariums, you may find it more difficult to find the right fish. New saltwater aquariums will need to start off with a population of fish that are hardy, easy to manage and won’t be aggressive towards others.

Even if you think that a certain fish comes from the ocean, or you have seen before in established reef tanks, that doesn’t mean they should be included in home aquariums. Most pet stores will not be knowledgeable or advertise which fish to avoid, so it is helpful to do a bit of research. Here are several varieties of fish that would do more harm than good in a new custom aquarium:

Groupers

Although groupers are a smaller than a lot of other fish, they can still prove to be hostile to your custom aquarium’s fish population. They have mouths that will expand to be quite large. Therefore, they will eat most anything alive that will fit inside of it. Unless you have a tank that is at least 200 gallons and include large fish that can take care of themselves, it is best to not include Groupers in your saltwater aquarium.

Mandarinfish

You may be tempted at first to purchase Mandarin fish for several reasons. Their unique coloring and patterns are a reminder of beautiful coral reefs. They are affordable, known to be disease resistant, and their smaller size will seem beneficial for not overtaking space in your custom aquarium.

This might all sound well and good, but the Mandarin’s  picky diets will be a big problem. You will find it difficult to keep them satisfied since they are dependent on eating copepods and will avoid most other general saltwater aquarium foods. It is difficult to have this type of fish survive in less established aquariums. Large reef tanks with a plentiful population of copepods will keep them healthy and satisfied.

Bluestreak Cleaner Wrasse

Similar to the Mandarin fish, the Bluestreak Cleaner Wrasse are also picky eaters and would probably starve in most saltwater aquariums. Eating parasites off of other fish is what composes their diet. In new saltwater aquariums, there will not be enough parasites to feed them.

In established saltwater aquariums, these are both helpful and entertaining fish. Their normal behavior includes zipping around in a fun spectacle and cleaning off dead scales and parasites from other fish.

Mollies/Guppies

These fish come from brackish waters. This type of water is considered to be something in between fresh water and salt water. It may not be the best choice at first, but once you get your aquarium going, these are fish that can slowly acclimate themselves to a completely saltwater aquarium environment.

You will also need to prepare yourself to expect more fish than you began with. Mollies/Guppies actively breed in captivity.

Damselfish

Avoid the Damselfish at all costs. They are very destructive to the rest of the fish population in saltwater aquariums. Your other fish will find it hard to live with one.

Don’t let their flowy angel-like appearance fool you, they are some of the most aggressive and territorial fish around. A damselfish will chase around other fish to the point that they die from exhaustion. Their competitive nature will also prevent other fish from eating in you custom aquarium.

Getting the Right Saltwater Fish for a Custom Aquarium

A good saltwater starter fish will be able to tolerate less than perfect conditions. Choose fish that are known to be disease resistant, peaceful at co-habiting, and are easy to manage. The fish in our list just don’t make the cut. By referencing this list of saltwater fish to avoid, it should help you establish a flourishing new saltwater aquarium with a minimum of fuss.

If you’re thinking of adding a custom aquarium for your home or business in the Los Angeles area, be sure to Aquatech Aquarium Service. Picking the right fish from the start is the key to a successful and enjoyable custom aquarium, and Aquatech can help!