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hollindalek
Guest
Hope someone can help . I've got a 140 gallon holding tank With a basic biological filter i have heated the tank over the winter, usual stuff in the filter a green sponge a blackish sponge and filter wool and not forgetting the media . It holds at the mo one fish a foot long Koi . I have just done a water change and noticed when cleaning out the sponges, that there are small i'd say 1 cm long red worms in the sponge's . Not worried if they pose no harm but can anyone give me some idea's of what they are and if they will harm my fish. I