Hole in the Head

[fish fanatic]

Hey there. I'm new to this message board, but not to aquariums. However, I have come up with something that I haven't seen before. My Red Devil has somehow come to get hole in the head. Does anyone have any advice on what to do? I have two electric yellows in the tank too, but I'd be able to take them out if I had to. By the way, this is in a 55 gallon tank, set up about a month or two ago.

[FinAddict]

I had the same problem several years ago and it was a parasite that burrows into the head. I cannot remember what it was right now but I will try to find out.

[AquariumPro]

Hello!

OK, I finally got a chance to answer this one. Sorry for the delay.

The disease "Hole in the Head" is actually not a disease, it is a symptom that is used to describe any erosion at the anterior end (on the sides of the head) of the lateral line system of a fish, which may be observed as a visible line of pores that run the length of the body below the dorsal fin. The condition may be caused by several things, and only one of them is a disease, which used to be a common problem, but nowadays is quite rare. I'll cover the first two causes first, as these are the most common, but first I'll address how the condition starts.

Whether it is a disease or a stress factor that cause the problem, the actual erosion which creates the holes in the head of fish are caused by flesh-eating bacteria. The problem starts with microscopic holes in or near the lateral line or a widening and irritation of the lateral line pores which are either caused by bad nutrition, low-level voltage in the water, or a small flagellate one-celled parasite called Spironucleus. Once the holes form or the lateral line pores dilate, bacteria set in and infect the afflicted area. These bacteria actually make the problem worse, and therefore visible to the naked eye.

The primary cause of lateral line problems or "hole in the head" is usually poor nutrition over a long period of time. If you feed a lot of the same food, such as feeder fish or pelleted foods to the Red Devil, after a while, the poor diet begins to affect the fish, and this usually manifests itself as erosion in the lateral line system. Fish should be fed a wide, varied diet including different frozen foods. If you bought the fish recently, the problem may have already existed when you bought it, but was not yet visible.

Another cause of this problem is loose voltage in the water, usually from old power heads or heaters, but sometimes from badly-grounded lights. Grounding the aquarium with a ground probe eliminates the problem. You can buy them at any good aquarium store or on our web site under aquarium accessories.

NOW, please be aware that the following is a very over-simplified and somewhat inaccurate life history, but entire chapters have been written on the subject, so I've shortened things a bit. You can read more on Spironucleus in any good fish disease book.

The last common cause of this problem is caused by Spironucleus, a parasite that is commonly found in the gut of many fish and is spread by fish eating eachother's feces. In the intestines, these critters do little or no harm, lying dormant. However, if the fish becomes stressed, due to incompatability, or bad water conditions, etc., the fish will stop secreting the protective mucus inside the gut, which allows Spironucleus to eat through the intestinal wall. The parasite then burrows into the nerves that lead to the lateral line, and make their way to the head where they exit the body of the fish to breed in the water. This leaves little holes in the head, and then the bacteria infect these holes and eat away the flesh.

If it is determined, through process of elimination, that diet or voltage are not the causes, treatment of "hole-in-the-head disease" involves two things:

1) Adding salt to the water to kill the bacteria and cleaning the aquarium to provide good water quality. Tablespoon of AQUARIUM salt per ten gallons of water is dissolved in some water and slowly added to the tank after a water change.
2) Some Metronidazole (Hex a Mit - See our Medications) should be added to some partially defrosted frozen food (about four capsules emptied onto and mixed with 4 ounces of food), the food then re-frozen, and this food should be fed exclusively for two weeks.

Many books offer a much more detailed explanation of the disease, and I highly recommend you do some reading if you have further questions.