I enjoy keeping both saltwater and freshwater fish tanks and sharing my knowledge with other aquarists.

Setting up a new saltwater tank can be an extremely expensive process, so it is imperative that you have a plan in place before starting to purchase fish for the cycling process. A single saltwater fish can run as much as $500, and putting it in a situation that will certainly kill it is not advisable.

Understand the Nitrogen Cycle

The first thing you need to know is what the nitrogen cycle of an aquarium is. Once you understand the nitrogen cycle, you will understand that you need fish that are resistant to ammonia poisoning and/or nitrites. This is only the first step in determining which fish you are going to use.

Specimen or Community Tank?

Next, you need to determine whether you will be keeping a specimen tank or a community tank. A specimen tank is usually used to accommodate overly aggressive fish, while the community tank allows for several species to live together. Understanding these things will help you determine what types of hardy fish are used to cycle a tank like the one you are going to set up.

Cycling a Saltwater Tank With Live Fish

When you add fish to the tank for the first time, be sure not to add more than 25% of the total future occupancy of the tank. If you do, then the ammonia levels will rise too fast for your biological system to keep up with, and you will kill your fish.

Once you have added the first batch of fish to your tank, you should do 25% water changes weekly for the first three to four weeks to help maintain safe water chemistry for your fish. Monitor the ammonia and nitrite levels with a monitoring kit and add further fish slowly, at the rate of one every two weeks, until you have fully stocked your aquarium. Be sure to add the most sensitive fish last as there will be mini ammonia spikes with every new tank addition.

Types of Hardy Fish Used to Cycle a Tank

There are many types of saltwater fish that can be used to cycle a new tank. The following list is not all-inclusive but does contain many of the most common varieties available on the market today. There are two separate lists, one for community fish and one for aggressive fish. The fish marked with asterisks are especially suitable for starter fish.

Community Fish

Aggressive Fish

As with most saltwater species, the clownfish and damsels do not do particularly well with others of their kind. Use only one type of each of these fish in your setup. When asking what types of hardy fish are used to cycle a tank, refer to these lists.