Filters for shrimp tanks

The short answer

A filter does two jobs in a shrimp tank. It gives beneficial bacteria a surface to live on, and those bacteria turn ammonia and nitrite into less harmful nitrate. It also keeps water moving so oxygen reaches the whole tank. Shrimp are small and the shrimplets are tiny, so the main question is how to filter without harming them.

Why sponge filters are popular

A sponge filter is a block of foam on a lift tube, powered by an air pump. Bubbles rise through the tube and pull water through the sponge. The flow is gentle, there is no open intake for baby shrimp to be pulled into, and the sponge surface grows biofilm that shrimp pick at constantly. They are inexpensive and simple to run. Use airline tubing with a check valve so water cannot siphon back into the pump if the power goes out.

Using other filters safely

Hang-on-back and canister filters can work well, but their intakes are a risk to baby shrimp. Fit a sponge pre-filter or a fine intake guard made for shrimp over the intake tube, and check that it is seated firmly. If the outlet is strong, point it at the glass or the surface, or use a spray bar or baffle so the water is not blasting across the tank.

Flow and placement

Shrimp do best with gentle, steady movement. If they cling to one corner or keep hiding, the flow may be too strong. Plants and moss give them places to rest out of the current; see live plants for shrimp. A new tank needs its filter running for weeks before shrimp go in; see cycling a shrimp tank.

Cleaning the filter

Clean only when the flow has visibly slowed, not on a fixed schedule, because a little mulm in the sponge is normal and useful. When you do, take some tank water out during a water change into a bucket and squeeze the sponge gently in it. Do not rinse filter media under the tap. San Diego tap water contains chloramine, which can kill the beneficial bacteria in the sponge. Avoid replacing all the media at once, since that removes most of the bacteria that keep the tank stable.

Neocaridina and Caridina

The same filtering approach suits both. Caridina tanks are less forgiving, so keep their filters running without interruption and avoid sudden changes in flow or media. See shrimp tank setup for the rest of the tank.

Questions we get asked

What is the best filter for a shrimp tank?

A sponge filter is the usual choice. It is driven by an air pump, gives gentle flow, cannot pull baby shrimp in, and its sponge grows biofilm that shrimp graze on. Other filters work if the intake is covered with a sponge.

Can baby shrimp get sucked into a filter?

Yes, on filters with an open intake. Slip a sponge pre-filter or a fine intake guard over the intake tube so water passes through but shrimplets cannot. Sponge filters have no such risk.

How do I clean a shrimp tank filter?

Squeeze the sponge or media gently in a bucket of tank water taken during a water change, only when flow has slowed. Do not rinse it in tap water, because the chloramine in San Diego tap water can kill the beneficial bacteria living in it.

Is strong water flow bad for shrimp?

Very strong flow can tire shrimp and push them around, and they tend to hide from it. Aim for gentle, steady movement and make sure there are plants or moss to rest in. Spray bars or baffles can soften a strong outlet.

Do I need a filter in a shrimp tank?

Most keepers use one, because the filter's surfaces hold the bacteria that process ammonia and nitrite, and it moves water around. Heavily planted, lightly stocked tanks are sometimes run with minimal filtration, but a sponge filter is cheap insurance.

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