What is Chaeto

Chaetomorpha or "Chaeto" algae is a green macro algae from the Division Chlorophyta and is one of the more common plants to keep in your marine aquarium to help maintain your water purity. The most common species is Chaetomorpha linum and is probably what is in your tank.

This plant grows in filamentous strands and resembles a tangled ball of fishing line. Each individual cell is tubular in shape. Although it can be placed in the main aquarium, active growth may make it a nuisance and is best kept in the refugium. Chaeto should be illuminated 'opposite the main aquarium', i.e., when the aquarium lights go off, the refugium light goes on. This helps to reduce the nightly pH swings that can occur in our marine reef aquariums. In general, most reefers will illuminate for 10-12 hours per day.

Other species include Chaetomorpha cannibina and antennina. Under the right conditions, this macro can virtually 'vacuum' your aquarium clean of nitrates and phosphates. Chaeto is generally kept in a refugium under moderate to high lighting and grows into a large fuzzy ball. It does best with good water flow, and, in  some refugiums, will need to be 'de-bulked' over time. In so doing, this reduces the mass of chaeto as it enlarges, ridding it of accumulated debris. You may even have to rinse it in aquarium water like a sponge. This is probably the most important task you will have to do to it to maintain it's health. When aquacultured, chaeto is usually tumbled, however, in moderate to high water flow, it should do fine.

Chaetomorpha linum is free floating algae that will not attach itself to anything in your aquarium unlike Caulerpa Sp. that quickly spread through a root system and will attach to most anything (ie. rocks, coral, glass, pumps, etc.). Caulerpa algae can be quite invasive and problematic. Chaeto is my favorite as a nutrient exporter and one of the reasons I prefer it is that it will not 'go sexual' like Caulerpa and release nutrients and reproductive products back into the water column.

Chaeto is a controllable macro algae. The basic idea is that desirable macro algae, such as chaeto, eat up the same nutrients as undesirable algae. For example, Byopsis, green hair, cyano, etc. Thus, out competing them for nutrients.

The idea is to grow the chaeto in an environment (a refugium or sump) that allows you to prune it as it grows, thus, removing the nutrients it has absorbed. As the chaeto grows and absorbs excess nutrients in your reef system it will out compete other nuisance algae in your tank. Regular pruning of the chaeto is the key to extracting dissolved organic wastes from the water. The chaeto takes it in and you take it out. This process of removing nutrient buildup is generally called "nutrient export".

Pruning your chaeto gives you the opportunity to help the natural ecosystem. You can give your pruned chaeto to a fellow reef aquarium hobbyist, thus, no need for them to buy something taken from the wild. You are now part of the aquaculture movement. Your newly aquacultured chaeto can even be traded for other aquacultured reef specimens such as coral frags. Some find they can produce a small income from there chaeto prunings on eBay. Hey, every little bit counts in this hobby.

Chaeto housed in a refugium will act as a spawning ground for desirable crustaceans such as copepods and amphipods to thrive and help feed and clean your tank.