Electric Blue Crayfish Tankmates

[EvlynnK]

Hello! I’ll soon be stocking a 75g tank as a beginner and hope to keep an electric blue crayfish from the local pet store. It’s very small (<2 inches) and currently living with various smaller fish. What kind of fish would be safe to keep with it? Here are some of the species I was considering stocking with:

-swordtails
-glass catfish
-rummynose tetras
-sparkling gourami
-platies
-cherry barbs

Would any of these be safe? Also would one crayfish be enough to help keep the tank clean or should I add another algae eater? Thank you!

 

[Colin_T]

Hi and welcome to the forum

Crayfish are best kept in a single species tank because they are nocturnal scavengers/ predators and will catch and eat fish at night. They also eat plants, which is good for them but not the best for a nicely decorated tank.

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Algae grows from excess light or nutrients, or not enough plants to use the light and nutrients. If you get lots of green algae growing on the glass and ornaments, then reduce the lighting time by an hour a day and monitor the algae over the next few weeks. You can also add some more live plants to the tank to use the extra light. Floating plants like Water Sprite will reduce the light getting into the tank and reduce the algae.

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What are the tank dimensions (length x width x height)?

What is the GH (general hardness) and pH of your water supply. This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

You have a list of fish that come from hard water (swordtails and platies) and fish that come from soft water (catfish, tetras, barbs gouramis). You need to know what the GH is before you get any fish because soft water fishes don't do well in hard water, and vice versa.

If your water is hard and has lots of minerals in (GH above 250ppm) then keep livebearers (swordtails, guppies, platies, mollies), rainbowfish or African Rift Lake cichlids.

If your water is soft and has no minerals in (GH below 150ppm) then keep tetras, barbs, gouramis and catfish.

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Regarding the livebearers, do not keep swordtails and platies together in the same tank. They hybridise and you end up with cross bred fish. And they are already messed up enough due to inbreeding at the fish farms.

If your water is hard and you want to keep livebearers, get a group of males or females but not both. If you want both sexes then have 1 male and at least 6 (preferably 10) females. This reduces the stress on the females. But find out what the GH is before you get any fish.

 

[Jordan_Deus]

I have an Electric Blue Crayfish in a 25 gallon.

I agree with everything Collin wrote. Crayfish will eat anything they can get their claws on, and that's the key. If you can keep your crayfish at the bottom of the tank (no decorations or filter pipes to climb) then top dwelling fish like hatchetfish, African Butterfly fish, some Pencilfish, etc. could work. Otherwise active fish that don't sleep on the bottom could work.

In my tank I have a colony of some 80 wild cherry shrimp. They are too fast for the crayfish to catch. That said, I'm sure he manages to catch and eat one on occasion, but the population is so big and reproduces so fast it doesn't matter. I also have Ancistrus (BN Pleco) fry in with him. They are fast, and nocturnal so yet to have a casualty. I do remove them once they reach 2 inches though, don't have a full-grown Ancistrus with him.

Take into account, that if your crayfish manages to catch it, he'll eat it, no questions asked.

My crayfish is fine (relatively) in a planted tank. I assume this is also related to it's temperament. He does eat plants, but for the most part, he'll only eat the moss. At the beginning he would tear all plants to shreads. I added plants like apontogeton ulvacus, vallisneria, and tons of Christmas Moss. Very resilient plants eventually, the plants got big enough that he left them alone (had some water lotus murdered though). He will take off the occasional leaf but for the most part he sticks to the moss, seeing as there's so much thats not an issue. He will also rearrange the substrate at times. Point is, you can get plants to grow with the crayfish, but you'll be limited to what you can grow if at all.

Edit: It's important to have a lid as they are escape artists. Also all the fish I've recommended need to be compatible with your water parameters.

I've added some pictures (ignore the claw laying on the ground, my crayfish molted two days ago and hasn't finished eating the exoskeleton).

 

[EvlynnK]

Thank you for your answers! I’ll take everything into account.

 

[Byron]

It's already been said, but just to add another voice...crayfish and fish do not mix. What stores do in their tanks can never be taken as acceptable long-term. Stores intend selling the fish quickly, and for the limited time the fish and crayfish are in their tank the animals are so stressed out they rarely behave normally. Once settled in a home tank--which will be their remaining life, remember, until they die hopefully of old age--they need a more appropriate home suited to their individual needs. And fish and crayfish do not mix.