I have a 10L tank with 3 guppies and 1 patty all male. and a sail. I am new to fish I got them for my kid who wanted a pet. I do regular water changes about ones every 2 weeks. I have live pants. Lately my guppies have been hanging by the heater my tank is at 76° and one has been swimming with his tail down. I ordered a water test kit so I will check levels ones it gets here. I just want to make sure they are healthy and doing good. I attached a picture of what my fish is doing