Beginner · 4 min read

What Is a Cleanup Crew?

A cleanup crew (CUC) is a group of small invertebrates — usually isopods and springtails — that live in the substrate of your bioactive enclosure. Their job is to break down waste, dead plant matter, mold, and uneaten food before it becomes a problem for your animal.

Think of them as your enclosure's built-in janitorial team. They work 24/7, they don't need to be fed separately, and they actually improve the environment for your animal while they do it.

What Happens Without One

Without a cleanup crew, waste builds up in the substrate. That breakdown process still happens — but it happens through bacterial decomposition, which produces harmful byproducts like ammonia. In a closed enclosure, ammonia buildup is toxic to your animal and can cause serious respiratory and skin issues over time.

You also get mold. Uneaten feeder insects, plant debris, and feces are all food for mold spores. Once mold takes hold in a substrate, it spreads fast and is extremely difficult to get rid of without tearing down the entire enclosure.

The Science Behind It

Isopods and springtails are detritivores — organisms that feed on dead and decaying organic matter. This isn't just a hobby hack; it's ecology. Research in soil science has consistently shown that detritivore communities accelerate nutrient cycling, reduce pathogenic bacterial load, and improve soil structure in closed systems (Hopkin, 1997; Seastedt, 1984).

In plain terms: they eat the bad stuff and turn it into something the plants can use. That nutrient cycle is what makes a bioactive enclosure genuinely self-sustaining rather than just decorative.

Springtails in particular are well-studied for their role in mold suppression. They actively seek out and consume fungal growth, including the early-stage mold that appears on substrate surfaces and feeder remains. A healthy springtail colony is one of the most effective mold prevention tools available to a keeper (Ponge, 2000).

Isopods vs. Springtails — What's the Difference?

Choosing the Right Species

Not every cleanup crew species works for every enclosure. The two most important factors are temperature and humidity — your CUC needs to be able to survive in the same conditions as your animal.

How Many Do You Need?

More than you think. A common beginner mistake is adding too few isopods and expecting them to keep up with waste production. A general starting point is 25–50 isopods and a culture of springtails per 10 gallons of enclosure volume. Give them time to establish and breed — a healthy colony takes 4–8 weeks to reach full working capacity.

If you're adding a CUC to an existing enclosure, start with a slightly higher number to compensate for any existing waste load in the substrate.

A Note on Tarantula Enclosures

Isopods and springtails are safe to use in most tarantula bioactive setups, including terrestrial and fossorial species. Some keepers worry that their tarantula will eat the isopods — and while some individuals do pick them off, a healthy colony reproduces fast enough to stay ahead of predation. Springtails are generally too small and fast to be caught regularly.

For spiderlings, stick to springtails only until the enclosure is large enough to support an isopod colony without the sling treating them as a primary food source.