anyone know why eels try to escape from their tanks?

[fugu]

would anyone know why eels try to escape from their tanks? i have a tight lidded tank but i feel that due to the hot weather here i might not have enough oxygen in the sytem.any ideas please?

 

[dlight692000]

eels have poor eye sight and they chase their food out of tanks, they are almost blind and if they smell somthing they think it is food so they chase it and somtimes out of the tank.