Does anybody change the temperature of their fish tank so the fish can tell between different seasons?

no - I don't think they need to know about a change in seasons - they are fish - they wouldn't remember anything about it anyway.

Only if they want to make their fish sick!

I've never heard of that actually.

i know someone who tried to simulate a thunderstorm by making alot of noise and dropping the temperature and putting the light on and off quickly. I think some of the fish bred after that. If you are trying to breed discus, don't do this ...it could be an expensive mistake

I never heard of that either. I think the whole reason for having a thermometer is to keep the temperature constant.

I only use a heater during the colder months when the water temps drops too low for whatever fish I have. So they get the summer, fall and spring temps. The only tropical fish I have are guppies and a betta. My guppies breed like they are the last of their species any time of the year so it doesn't effect them. And my betta I don't want to breed. I know there are some fish that will only breed certain times of the year and you can control that yourself using a heater. The rise in temp can trigger spawning.

Tell you something, I once cleaned out my daughters goldfish bowl, I thought `For a treat I will put the fish in some warm water while I clean the bowl`..... Well, I put the fish in the sink and started to clean the bowl in the bath, after five minutes I had cleaned the bowl and turned to see the fish, at least 3 times bigger than it was when I put it in, also, it was motionless and floating..... I panicked (as you do) and quickly popped the fish back into the new bowl of tepid water and put it back into my daughters room, and ran off! Funnily enough, I thought the fish was dead or had suffered som `fishy brain damage`, but, in the morning the fish was fine. weird, but a cautionary `tail`!

nope .. i have a Heater that comes on when its under 70f. ..I have 2 Walking Catfish ..both are 7 years old and live in a 6x2x2 foot tank...

No. A fish that needs it warm is likely to originate from warm parts of the world and would not experience much in the way of seasonal temperature change. Don't mess with a tropical fish's temperature too far, it would not be good for them.