Worms!

More than like they are Planaria or Nematodes that are caused by excessive nutrients/lack of maintenance, aka a dirty tank.
The extra nutrients from a messy live food was probably the kicker that allowed them to blossom from a latent population in your substrate to infestation level.

The best course of action is to;
1) Very thoroughly and deeply vacuum your substrate, do this daily for about a week.

2) Rinse your filter media and media chamber in a bucket of tankwater.

3) Raise your temp (slowly) to 86'-90'f.
Remember to add more aeration to counter O2 depletion due to high temp.

4) Don't feed for aprox five days (will not hurt your fish) and then cut back on regular feedings (smaller portions and less frequency).

5) Add a dose of salt to the water, standard aquarium dosage (1tblspn per 5gal) is fine but you may dose higher (up to 1.001 SG(specific gravity).

sounds like a case of nematodes.



There are approximately 10,000 to 10,000,000 species in the Phylum Nematoda. Free-living (ie without a 'host') forms can reach sizes between 1mm to 2 cm (0.04"- 0.8"). Nematodes that live in the aquarium usually reside in the gravel, but when disturbed they swim in a snake like manner. Much like that of a sea snake. They can be easily seen in a bucket after cleaning the gravel.

There are three types of nematodes: parasitic, scavengers and herbivores. The vast majority of nematodes are parasitic. All three are able to live within the aquarium; however the scavengers are usually the most common.

Nematodes can be introduced to the aquarium in egg or adult form. Eggs can be present in almost anything that you add to your aquarium; feeders, live plants, driftwood etc. Adult worms are more likely to be introduced by live plants and in the water accompanying your feeder fish.

Populations of nematodes can be reduced or elimated by:

1. Set out bait like meat in a mesh bag. remove the bait a few hours after the lights go out on the tank. it should be covered with nematodes. throw away and repeat until the population goes down.

2. add nematode eating fish to the tank. such species include the paradise fish, betta, pelvicachromis pulcher and many species of gourami

3. vacuum the gravel very well and do a 50% water change. often, nematodes proliferate when the tank is too dirty. this will remove not only some nematodes but their food source as well.

4. reduce the foods added to the tank. nematodes often proliferate if too much excess food is provided.