“I found these worms in my isopod terrarium”, writes Cynthia about the translucent worm-like creature pictured below. “I have been searching but am unable to find out what worm it is. Would be grateful for some help! The worms are less than 5mm long and this is the clearest photo I could get. The white part is the head and all of them are coloured this way. They are too small for my eyes to see if they are segmented or not. They seem to gravitate towards damp areas in the terrarium. I live in Singapore, which is a warm and humid place. Any ideas?” To begin with, we want to point out how cool it is that Cynthia has an isopod terrarium: it’s not everyday you hear that, and we appreciate her appreciation of such critters.

Now, we do have some ideas as to what this could be, thanks to her photo, as well as the helpful context she provided. Based on the appearance alone, we would say this would either be a flea larva or a fungus gnat larva, but based on the location of discovery, and the context that Cynthia provided, we would conclude that this is a fungus gnat larva. Fungus gnats are a species of fly that particularly like damp environments where they can lay their eggs in soil: which seems to be what happened in Cynthia’s terrarium. The adult gnats are harmless to humans and plants, but the larvae can be damaging to plants, as they tend to chew on roots, especially the roots of young plants.

When the conditions are especially warm and moist, fungus gnat larvae can even leave trails of slime behind, so Cynthia might want to be on the lookout for those, as that would confirm this identification. Unless Cynthia’s isopods are among the few species that are predators, we would recommend that she try to remove these larvae from her terrarium, as they mature at an incredible rate. It only takes the eggs three days to hatch, and then it takes the larvae ten days until they begin pupation. Then, just four days later, they will be fully transformed into an adult gnat. In total, it does even take three weeks to make an entire generation of fungus gnats! One way to trap larvae is with potato pieces: if they swarm the potatoes, then Cynthia can just take out the larvae-covered pieces and throw them outside. Likewise, she can also use fly traps in her home to catch the adult gnats, so that they do not lay more eggs in her terrarium.

In conclusion, we think that the clear worm-like creatures Cynthia has been finding in her terrarium are fungus gnat larvae. We hope the information provided proves helpful, and we wish Cynthia, as well as her isopods, the very best!

• 
•