What filter should I get for my Platy fry. The current Aquaclear 20 is too strong has already sucked my fry three times into it (thankfully no injuries or damage). I can't use a sponge filter or any filter that requires an air pump because the air pump is far about 15 metres away. The aquarium is 5 gallons and currently houses 4 fry. Any suggestions on brands/types of filters?