Blue Crayfish Isnt Eating


My mother's 4 inch blue cray hasnt been wanting to eat for over a week.
He completely ignores any food she gives him, including his favourite thawed peas and bloodworms, and she isn't sure what to do anymore.

He's been healthy and active the first 2 months right up until last month. We kept finding him turning himself upside down for a week and was less active during the day. A quick search online said this was to help himself molt, but he never molted.
He still remained less active and hidden.
While I was out of town last saturday, the tank got a 100% water change after I got a call saying he was "lethargic looking" and curled up in a open corner instead of in his hiding spots.
Apparently, immediately after the water change he got ridiculously active, but still refused to eat. He's back to being active in the evening.

He didnt stop eating when he had his previous molt, neither did he turn himself upside down randomly.

Any idea about what's up with him?

Lives in a half full 30gal
Filters are; AquaClear 50 hob, a large diy sponge filter with a 100gph pump, and a small riparium basket with pothos and what looks like neanthe bella palm.
Weekly 50% water changes.
Tank has small pieces of eggshells for calcium.
Tankmates: some MTS and a single fat feeder danio he decided to befriend since it swims between his legs and claws without a care in the world.

pH: 7.5
Ammonia: 0ppm
Nitrite: 0ppm
Nitrate: 5.0 ppm

His normal diet consists of a mix of
Thawed peas, cucumber, zuchini, lettuce, spinach, carrots, homemade wafers and occasional bloodworms and fish.
The homemade wafers are usually made out of broccoli, duckweed, white fish, garlic, and any of the veggies above.


thorough post.. obviously you know your stuff and your stocking is fine..that is not the concern.

At first my response was going to be about how they are scavengers and even though I NEVER saw my blue crayfish eating, he was growing and healthy so he had to be scavenging at night.

However as this post progressed it sounds more and more like sickness of some sort. Does his color look paler than usual? Is he thinner than he should be? Maybe some type of bacterial infection or even a parasite? Community tanks almost always carry these but the inhabitants grow resistant so its not a problem. I am more specialized in fish sickness but I can't imagine inverts are that different.

The problem is that I don't know what meds will be safe for a blue crayfish. I know that my amano shrimp were fine when I treated with "API General Cure" for internal parasites, so I would assume the crayfish would be fine.
  • Thread Starter


Thanks for the reply!

My mother's cray used to always come out "asking for food" and would happily eat up at around 5pm.
I had thought he was probably scavanging, but with his current tank setup, there is nothing for him to scavenge.
Aside from what he's given of course, and possibly a leaf of the pothos but it has no signs of being damaged. The plant itself shouldnt cause illness though, only some irritation around the gills.

After writing the post yesterday, I had decided to plant a whole bunch of waterweed in his tank to see if he decided to reconnect with his inner lawnmower. He at least checked them out and took a single bite of it before losing interest. He did however uproot a few since he kept getting tangled up in them.

You're right, it does sound like some sort of illness. I've done a bit of digging around and there doesn't seem to be all that much on pet crayfish illnesses and diseases.
As for parasites, I've only managed to find information regarding external parasites.
It seems most of them do neither good nor harm to crays, and others seem to even benefit them. This cray has no visible external parasites but I'll keep digging for more information though.

I'll look into API general cure, so far it seems safe for crays although not many reports on it.

I was wondering if possibly maintaining a very low salinity using aquarium salt would help?

A while back my cherry shrimps had some external parasites that gave them a crown or a faux-hawk and the treatment was a dip in aquarium salt water. Some people also suggested maintining a very low salinity level of the tank to prevent a new outbreak. I don't know if this would work on a blue crayfish though.

During the day, he seems to spend most of his time with his tail curled underneath him. I'm not sure about this behaviour.

I'm also worried that he hasnt molted despite turning himself upsidedown. Should I start dosing iodine?

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