Everything you ever wanted to know about HITH / HLLE… but were afraid to ask!

Written, edited, and published by Adam Dagna

HITH or Hole In The Head
Hole in the head, or HITH, is also known as head and lateral line erosion, or HLLE. They are just different ways of describing the same disease. It affects the sensory organs in the face as well as those along the lateral lines, causing pitting in both regions, hence its name. Much of this disease remains a mystery because many of the studies done have been inconclusive or contradictory in their findings. However there are generally four theories that stand out and have been substantiated numerous times by different studies: environment, diet, “the carbon theory”, and Heximita infections.

Environmental causes can be divided up into two major sub categories, those being water conditions, and stress. Poor water conditions have been linked to many cases of HITH and can be a major factor in its onset. It is important to say that this is pretty much a blanket category encompassing all aquarium disease, as problems are rarely seen where water quality is not an issue. It is possible to have diseased fish and have perfect water but this it is uncommon at best. That being said, proper water filtration and movement is a must. As a rule of thumb your ammonia should read 0, nitrites 0, and nitrates should be less then 40 ppm, and less then 10 ppm is ideal. Nitrates have been linked in some studies to the development of HITH where a fish is kept for long periods of time in water with levels exceeding 40 ppm. Stress can come in many different forms, but competition between tank mates is one to watch in the aquarium. This usually manifests itself in two ways, either unfair competition for food, or pestering. If you have fish of different aggression levels in the same tank (not necessarily fish of different species, as each fish has a different personality), one or both is likely. Either the more aggressive fish will pick at or straight out beat up the less aggressive fish or it will simply eat more then its share of food leaving the other with less then adequate portions. This is highly stressful and over time will wear at the fish’s immune system and can contribute directly to the next factor.

Diet is the most commonly accepted and supported cause of HITH. It is believed that the disease is more akin to scurvy, or rickets; both vitamin deficiency diseases in humans (scurvy is caused by not having enough vitamin C in your diet over extended periods; early sailors would get it because fresh fruit and vegetables could not be stored for long voyages). Just as the human body degenerates if proper diet is neglected for too long so do aquarium fish. If an unbalanced, or an out right improper diet is fed over a long period of time the fish can suffer greatly. Don’t mistake a fat fish with a healthy fish, just as you wouldn’t mistake a fat person for a healthy person. Simply eating food is not good enough; it has to be the right food. A link has been found between the development of HITH and a lack of calcium, phosphorous, and vitamins C & D. Many of the common fish foods sold in the hobby today are enriched with vitamins to make them more balanced, though supplemental vitamins can be added to them as well. Know the diet of your fish and be consistent, and varied. As a side note for carnivorous and semi-carnivorous fish such as Oscars, red devils, and Jaguars, feeder fish should never be chosen as a primary food source because they have virtually no nutritional value. In addition feeders contain the enzyme thaimase which breaks down thiamine. Thiamine is an important vitamin and if you use feeders as a large portion of your fish’s diet it WILL develop a thiamine deficiency. Fish fed exclusively or largely diets of feeder fish are extremely likely to develop HITH. They are also in high risk of contracting other diseases, such as ich, numerous other parasites, or fungal infections. It is important to resist the urge to watch your fish chase their food; it is for their own good.

The carbon theory is probably one of the most hotly debated concerning the cause of HITH. The idea is that the carbon used to remove harmful toxins from the water actually causes the disease. At first this may seem absurd and contrary to what you have read or been told, however when you take into account the number of cases of HITH directly related to carbon (i.e. HITH appears when carbon is introduced and disappears when carbon is removed) it is hard to argue with it. Many studies failed to produce results when testing for the carbon theory, as many fish with carbon in the tank did not come down with the disease, and this has lead to it being somewhat discredited as a real cause. In my experience the cause does not come so much from the carbon itself but from carbon dust. When carbon is shipped to the stores it is jolted and jostled across the country hundreds or thousands of miles in the back of a hauling truck. As the carbon particles rub against each other carbon dust is formed. Anyone who has ever used carbon knows this as the black sludge that comes off when it is washed. Improper or unthorough washing of carbon can lead to that dust being introduced to the water. This in turn causes the disease, so when the carbon and more importantly the carbon dust is removed the HITH goes into remission. Another theory is that prolonged use of carbon causes many vital trace elements to be absorbed, and this deficiency in the water leads the fish into the illness.

Hexamita was once believed to be the main cause of HITH, but has since been debunked as a major factor. This information has seemingly not gotten to the general public however as expensive drug treatments seem to be the first thing suggested by local fish stores to cure the disease. Heximita is an intestinal parasite that can affect many tropical fish, interrupting the ability to absorb nutrients through the intestinal wall. It has been found in many cases of HITH however they are usually in the pits and craters formed on the outside of the body, and are largely a non parasitic species commonly inhabiting aquarium water, while the intestines are clear of the true parasite. Many times cases of HITH have improved dramatically with the treatment of a hexamita drug, though there are equally as many that did not recover at all, showing no signs of improvement. It is believed that hexamita when found in relation to HITH is actually a matter of a secondary infection brought on by the suppressed immune function and not the cause of the HITH. In cases where hexamita is are present in the intestine treatment of the HITH can not begin until the infection is cured.How to treat HITH

Contrary to popular belief, and common fish store advice, HITH is actually very easy and extremely inexpensive to cure. It can be cured, or rather sent into remission in several easy steps. Just as a note I’ve found it is best if you follow the steps in the order they are listed, some steps are not vital to recovery but steps 1 and 2 are essential. It is interesting to note that this treatment does not requite expensive drugs, but relies on good diet and tank maintenance. Following these steps a fish can be cured with little or no money spent.

1) Feed a balanced and vitamin enriched diet. Get your fishes diet back on track and supplement whatever pellet food you choose with vitamins twice a week. If you can’t find any vitamin supplements at your fish store, just powder a common high quality multi-vitamin, then dissolve a small portion in some tank water and allow the pellets to absorb it. In addition feed a larger variety of foods, being sure that they are all relatively close to the fish’s natural diet. Some examples are earthworms, crickets, mealworms, beef heart, crayfish, shrimp, blood worms, or krill. The list could go on ad infinitum, and freeze dried versions of any of the above mentioned foods are good choices too. See the recipe below for a good balanced home made food.

2) Start doing water changes of at least 20% but not more then 50% every three days, usually 25-30% is sufficient. This is the only effective way to lower excess nitrates from the water, make sure that you vacuum the gravel at the same time, as detritus and feces can collect here without your knowing.

3) Add 1 tbs of aquarium salt to every 5-10 gallons of water. It is important not to use table salt as it is treated, kosher salt, marine/aquarium salt, or any untreated forms of salt are ok. Make sure to add new salt for water removed in water changes and be aware that once salt is in the tank it will stay there until removed by water changes so do not add more then what you removed.

4) Raise the temperature in the tank to 80-82° F.  This will increase the fish’s metabolic rate and decrease healing time. Be sure not to raise the temperature above 84-86° F as this can cause undue stress to the fish and is not productive for healing, also do not raise the temperature with out first following steps 1, 2 and 3, as you will simply cause the HITH to advance at a more rapid rate

5) Remove all carbon from your filters. This is a precautionary measure unless you know for a fact that the carbon is the main cause. In future purchase only high quality carbon, and make sure that it is thoroughly washed before addition back in the tank.  This is especially important if you are planning to treat per step 6, as carbon will remove medication from the water.

6) If all else fails or for very advanced cases it will be a good idea to treat the tank for Hexamita, follow the directions for dosing on the box, or bottle, and continue treatment for at least a week. Then go back to treating per steps 1-5.

Continue treatment until you notice the wounds healing, and getting smaller at this time, the temperature can be lowered to the normal for your fish. Salt can be reduced to 1 tbs per 10 gallons or slightly less. And water changes can be done weekly. It is very important that the diet be maintained for the life of the fish. For those of you who have tried all the steps above and are still struggling with HITH, check the next section of this article for other possible causes and their cures.

Other things which may helpReally the first step in treating HITH is knowing your fish even has it. The only way to know this is to watch your fish often enough so you know what normal appearance, and behavior is. If you don’t know what you fish looks like when it is healthy then there is no way to know that those pin holes in its head aren’t normal. Be familiar with your fish and how they respond to you, when there is a change you will notice and be able to respond to that problem sometimes even before external symptoms become pronounced. This is sound advice for diagnosing any disorder. You can’t know what is wrong unless you know what right looks like.Other possible causes

After sharing this article I have had the opportunity to talk to many people about their own cases of HITH, I have decided to add this section listing other causes that seem the likely culprit but are not commonly accepted as being a cause.

Stray Electrical Current Theory

If your fish mysteriously come down with HITH and your care is impeccable, or if your fish have a chronic problems with HITH generation after generation You might want to get a Voltmeter/Multitester. This device measures electrical currents. Place one of the probes directly into the tank water, and ground the other. The dial should read zero (0). Any reading over zero (0) and this could be your problem. Fish are very sensitive to water conditions and electricity in the water is a major source of stress. Buy a grounding probe and install it in your tank, then try and determine which piece of equipment is causing the leak and either replace or discard it (heaters and power heads are common problem items), also follow the steps listed above in the cure section to insure you are covering all possible causes, unless you want to try and verify that this was the only factor.

Boring Diet Syndrome Theory

There have been a number of people who have related to me mysterious cases of HITH with no discernible cause. When I asked their diet and feeding schedule all were feeding a commonly recommend diet; twice daily with strictly commercially produced pellet food. This has lead me to believe one of two things; either that Oscars fed healthy food, but a boring monotonous diet of one type of food will succumb to HITH over time. Or that these commercially produced foods are missing certain vitamins and minerals that need to be provided in other types of foods. Either way the cure is simple, feed numerous different types of food as well as pellets, and give a vitamin supplement twice a week. I would like to be clear that I am not recommending you stop using pellets as a main source of food, because they are an excellent source of basic nutrition, I am however suggesting that the diet may need to be more then just pellets for the fish to be healthy. At the very least you will have happier fish which is after all the name of the game.