Okay first of all my tank is 80 gallon (300 litre) i really need some help with those questions? but before ima tell you what i have in my tank 5 mollies and balloon mollies 4 guppies 3 angelfish and 5 platys and 6 swordtails and 2 gouramis.... 1-my fish start to die slowly after 1 month of buying them i lost 5 platies and 2 guppies and 2 balloon mollies and 1 yellow mollies which there's no signs of ich or anything at them my temp is 29c now stable i don't have a heater in the tank it's just the heat of the summer...it did reach 30c 31c 1 time but i did put a fan in the room and now it's stable at 29c (i don't have ac in the room) it could be possibly my temp right now killed them or what? iam getting crazy about losing fish every day or two. 2-I did a few testing (using sera test box) for ammonia nitrite and nitrate and ph and the results are ammonia: 0 nitrite 0 nitrate 10 and ph 7.5-8.0 i can't get it lower than that and i have 2 big woods in my tank i wanna know if ph have anything with my fish death? 3-before anything say try freeze bottles of water and put them i did try it it wasn't successful and my tank came with a lid that i cannot open it fully because the lid it's sticking with a filter on the back and my lights here's a picture as you see i cannot open it fully ... and yeah about the clip on fans for aquarium believe it or not but i can't find one in any pet store here in my country ...we have a clip on fans but not for aquariums would it work? I really cannot afford a chiller or ac in the room and i wanna know if the temp 29c (84f) is killing my tropical fish..or theres another reason...thanks.