Oh man, these are nasty, don't even need a picture. Here's one of my rams who had them so bad he had a prolapse trying to pass them.
The entire tank will have to be treated with fenbendazole (dog dewormer Panacur), even fish who aren't showing them. Others have had good luck with levamisole, if you can find it.
http://www.vetuk.co.uk/dog-worming-cat-worming-panacur-fenbendazole-wormers-c-17_43
My experience was with the Panacur granules, but I noticed they have a liquid now. That might be more water soluble and better for soaking their food, but I don't know the dosages for it. I don't think it's real critical to be exact, however.
This was for my 20 gallon tank with Bolivian Rams, a pleco, a ghost shrimp and a guppy, so adjust as necessary -
Do a water change first, then thaw a cube of bloodworms (or anything they'll eat) in some water with 1/2 gram (half a packet) of Panacur and perhaps a little garlic to disguise the taste, then pour the entire contents into tank. Feed them nothing but same medicated food for 4 days, but don't add more meds to the water. After 4 days do a water change and vacuum. It usually takes two treatments to eradicate completely, so repeat the treatment after two weeks time.
You may lose some fish anyway, but not necessarily. One of my rams who was infested is still with me, as is the shrimp and pleco. Good luck, Tony!
