Like most pets, hermit crabs occasionally get parasites. Sometimes these parasites are, in fact, distantly related to crabs, and few are more sensitive than hermit crabs to most chemicals. This means that many chemical treatments intended for amphibians or reptiles are not appropriate. You risk killing the crabs before the bugs. Other treatments exist, though, and you should be able to debug your pets without too much heartache.
Identify the bugs in the hermit crab tank. If they are tiny creatures crawling on the crabs and appear to be causing distress, they are most likely to be hermit crab mites. Use a magnifying glass to get a good look at them. There are numerous other little creatures that may take up residence, ranging from fruit flies to beetles, and most of them are harmless. The first line of defense is, however, the same.
Transfer your hermit crabs to a holding container.
Fill a small bowl with dechlorinated or spring water and set it to one side while it warms to room temperature. Prepare one bowl per hermit crab.
Boil the substrate, if gravel, and any rocks or other accessories for at least 20 minutes in distilled water and allow to cool. Alternatively, simply discard these items.
Wipe the tank down with plain water and rinse it.
Dry the tank before replacing the boiled substrate and accessories or adding new.
If the bugs are mites, submerge each hermit crab in a bowl of water for a few minutes. This should remove most, if not all, of the mites.
Return the hermit crabs to their tank.
Observe the crabs and their habitat closely for the next few days. If the bugs were mites and they return, you may need to use a commercial medication, available from aquarium and exotic pet suppliers, as per the instructions, or take the crabs to a vet with experience of arthropods. If the bugs were merely fruit flies, fungus gnats or another benign creature, just clean the tank again once their numbers reach annoying levels.
- Always sterilize new shells and other accessories by boiling before putting them in your tank.
- Quarantine new hermit crabs in a separate tank for a few weeks before introducing them to your main tank. They may be carrying parasites and need to be treated first.
- Only use medications specifically for hermit crabs -- those intended for vertebrates will almost certainly kill your pets.
- These are instructions for land hermit crabs. Marine hermit crabs do get parasites as well, although you might not call them bugs. However, the parasites and the treatments are different.
Judith Willson has been writing since 2009, specializing in environmental and scientific topics. She has written content for school websites and worked for a Glasgow newspaper. Willson has a Master of Arts in English from the University of Aberdeen, Scotland.