Who Gives A Fish Forums

i'm freaking out a bit here - this thing has a tiny woodlouse on its back, like 4-5mm long! i'm really concerned it might be a pest or something. is it something i should be worried about? should i try to carefully remove it?

nope still clueless

aw, feel kinda bad for it

I've identified it as an isopod. If I'm unable to remove it, I'm concerned it'll cause harm to the host.

yeah, its an isopod, if i cant get rid of it, its going to eat him

That thing is massive, you can't just yank it off or something?

lowlands wrote: ↑Wed Jul 30, 2025 10:48 pm yeah, its an isopod, if i cant get rid of it, its going to eat him

That thing is massive, you can't just yank it off or something?

I'm going to give it a shot, but I want to hear from skifletch first. Got my forceps at the ready, also prepped a freshwater dip, but the PH difference is massive, how do I raise it without using stuff like PHup?

lowlands wrote: ↑Wed Jul 30, 2025 10:48 pm yeah, its an isopod, if i cant get rid of it, its going to eat him

That thing is massive, you can't just yank it off or something?

I'm gonna try to remove it, just waiting to hear from skifletch first. Got my forceps at the ready, and I've also got a freshwater dip prepared, but the PH difference is huge. Does anyone know how I can raise the PH without using PHup? bicarb, maybe? just a guess lol

I'd try a freshwater dip first. If that doesn't work, then I'd attempt manual removal. If the isopod's really stuck, you might have to consider using a medication, something like Interceptor that's used for fleas and ticks on dogs and cats. It's a prescription med though, so getting it could be tough, but it does kill small pods like that one.

Oh my goodness, I just found this info by Ron Shimek about aquarium inverts, and I'm freaking out - you guys need to be careful too. Apparently, cirolanid isopods are like the ultimate reef bugs - they're huge, up to 8-9 cm long and a centimeter wide, although most are only a tenth of that size. They've got a pointed front, short antennae, and big eyes, and are usually white or gray to blend in with the substrate.

These isopods are not afraid of fish, on the contrary, they think they're a snack. They're often considered parasites, but that's relative - they just eat a bit of their prey over time. Large ones in the Pacific have been known to wait for an unsuspecting fish to swim by, then latch on and start eating its fins and tail. They can even slice open the fish and eat its blood and muscles - talk about a nightmare.

They can also attach to larger fish and eat their way into a major blood vessel, sucking blood and eating tissue until they're full. When they're done, they just detach and swim away. Tropical species often end up in reef tanks, either on a fish or in live rock. And you know what's even scarier? They usually target the most expensive or hard-to-replace fish.

If you're unlucky enough to have one of these isopods in your tank, it's a real challenge to remove it. If it's on a fish, you need to catch the fish first, which can be almost impossible. If you do manage to catch the fish, you can try to remove the isopod with forceps, but be extremely careful. The fish should then be isolated in a hospital tank and treated with antibiotics until the wound heals.

If the isopod leaves the fish, it's almost impossible to catch - they're too fast and can avoid nets easily. If it's a pregnant female, you've got a real problem on your hands. In that case, you've got three options: remove all the fish from the tank and wait for the isopods to starve, nuke the tank and remove all live rock and sand, or do nothing and risk losing all your fish.

Seffie x

ps - good luck with that little goby, route4. Do you have a small hospital tank?

I'm not allowed to set up another tank, but thanks a ton for all the info Seffie.

I got home and what did I see? The cleaner shrimp was on it, pinning the goby down and going to town on that isopod. It was literally pulling the thing apart.

I'm thrilled, victory is definitely mine.

Massive congrats, route4, so stoked the cleaner shrimp saved the day. Shrimps are literally the best, right? They rule, for sure.