Where I live it is really hot. I have a 5 gallon tank with babies and today I went to check on them and the temp was almost 90 degrees! I did a water change with cooler water and gradually got the temp down to 80 but I can't imagine it will stay low. I think the heat took its toll on a few of them as now they are just laying at the bottom of the tank. How hot is too hot and is a water change the best option?