Blue crayfish spazzing out!!!

[Jake tha snake]

Ok, so I'm having an issue with my blue crawfish I've had him for about a year now and I was cleaning and doing a water change and my 20 gallon hexagon Aquarium and I was finishing up and after I was adding the fish I thought I would add my albino Oscar to the large tank and him to see how they did together well obviously not too well because either he is in shock or something because I took the Oscar out and he acted like he was dead and his tail was curled up and he wasn't moving but when I barely touched him with the net he started flying all over the tank and Claws out and just completely spazzing out. what should I do?

 

[Colin_T]

Hi and welcome to the forum

Your thread is a bit hard to follow due to lack of full stops, but if I understand correctly you moved your fish out of their tank to do a water change and when you put them back in the tank, the crayfish freaked out?

There is no need to move fish out of their tank when you do water changes. If you don't already have a gravel cleaner, get a basic model gravel cleaner like the one in the following link. It will allow you to clean the gunk out of the gravel while you drain some water out of the tank. You can ask the pet shop to demonstrate it when you buy one. You don't need a fancy one with special feature, just a basic model like the one in the link.
https://www.about-goldfish.com/aquarium-cleaning.html

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Crayfish should not be kept with fish because they are nocturnal predators/ scavengers and will attack fish at night. And big fish like Oscars should not be kept with crayfish because Oscars eat crayfish.

A 20 gallon hexagonal tank is not big enough for an Oscar. The minimum sized aquarium for Oscar cichlids is 4 foot long x 18 inches wide x 18 inches high, and bigger is better.