I just bought this 6 dotted sleeper goby and it is displaying strange behaviour. It hasn’t been sifting sand and instead it just looks like it’s gasping for air. I have checked all the tanks levels and everything is normal. Any help would be great not sure if I should return it back to the store before it dies. Or if this is regular behaviour. Attached is a video of the breathing I’m talking about. Any tips would be great!