Anchor Worm

There are many small crustaceans (copepods) which are parasitic on fishes in one stage of their development. None of them are really important to the tropical fish fancier for they don't do too much damage. There is, however, a copepod belonging to the family Lernaeidae which warrants discussion. This crustacean looks more like a worm than a crustacean, but in its larval stages it manifests greater likeness to the copepods than to the trematodes.

The lernaceids, or Anchor Worms, have two free swimming stages in their life history. The first free swimming stage is right after they hatch from the eggs and they are called "nauplii." This is when they become parasitic upon the fish. After they have developed awhile they go through another stage and again become free swimming. Thi is the stage of maturity where they go about seeking a mate in order to reproduce.

Many species of anchor worms are known, but the species most familiar to aquarists is the fish parasite Lernaea carassii, named after the goldfish upon which it favors to develop. This parasite, like other anchor worms, attaches itself to the body of the host, either in the gills or any place on the body (or inside the mouth in some cases). In time it bores into the flesh of the host and sucks the blood from the small capillaries in the tissues of the fish. Soon afterwords teh familiar "bumps" and "tumors" show up.

Fortunately enough for tropical fish hobbyists the worms are large enough to be seen with the naked eye, and since the fish can be easily netted and handled all that must be done is to remove the worms from the fish's body. This can be done in either of two manners: one way is to prick the "tumor" and remove the worm with the needle. If the "tumor" is too tough, swab it with some salt first; other hobbyists prefer to "tweeze" the worm and tumor out all at once. We prefer the needle treatment for it seems that the "worm" will come loose once the capsule is broken and the entire organism can then be removed. The area should be swabbed with some peroxide or mercurochrome after the worm is removed.

There is no method other than the mechanical technique mentioned above to rid the fish of these worms.

Scientific literature intimates that different species of fishes play host to different species of anchor worms; this might well be the case, but the author has maintained aquaria where infected guppies were placed in with healthy goldfish and swordtails, and it wasn't three weeks before all the fishes had anchor worms on them.