I bought a 2.5 gallon fish tank and 3 fish. 2 were these beautiful transparent fish with either green, orange or pink around their edges and one was a danio. The 2 transparent fish, at different times, wedged themselves, upside down, behind the above-noted filter and died. We replaced them with Platy's, one of which also wedged itself behind the air filter and died. Has anybody else ever had this problem with this filter? Penn Plax says it has never happened before. If it is not the fllter, what could possible be causing my fish to die like this? Many thanks for your time.