Bacterial versus Fungal...Those little white tufts

By Steve Skinner

It should be noted that true fungal infections in marine aquaria are extremely rare and often misdiagnosed. Typically what are considered fungal problems will indeed be bacterial in nature. The more common causes being wounds from poor transport, netting, fish aggression or accidental abrasions within the aquarium.

In a healthy low nutrient system, these wounds will often healed by the fish's own immune system. In the absence of proper husbandry where water conditions have become nutrient rich coupled with an improper diet, a small calamity can quickly become a concern. Often developing into swollen or red areas, they can be accompanied by small white cotton “tufts” sometimes incorrectly attributed to fungal infections. Also referred to as fin or tail rot, these are in fact bacterial (Cytophaga-Flavobacterium) and in milder cases no medicinal treatment is needed.

Affecting proper water changes with well aged and aerated saltwater accompanied by a properly fortified diet will in less severe cases be all that is needed. As with Lymphocystis and Vibrio, the living conditions must be improved. Increased water changes with well aged and aerated saltwater is the best first step. By reducing the DOC and other nutrients within the system, it will effectively starve the fungi of the needed foods that sustain their growth. More importantly with the fungi as they are incapable of manufacturing their own food supply Once accomplished, the fish’s natural immune system in most cases will be able to heal the infected area.

The next step is improving the fish’s diet and reducing obvious signs of stress. Proper nutritious foods are an incredibly important part of maintaining or improving fish health and their natural immune system. With proper nutrition, an otherwise healthy fish will be able to heal itself of more simple infections without much interference from the hobbyist. That does not mean they don’t need a little helping hand. Enriching foods are the easiest and most effective means aside from natural food sources. With the many manufactured foods available, they become an easy alternative to healthier choices. Adding elements such as Selcon® , ZoeCon® or other vitamin supplements high in HUFA’s and essential lipids; boosts the immune system much like a human taking a chelated multivitamin. Beta Glucan (if available) is also a proven and powerful anti oxidant immune booster.

Reducing the stress of the fish within the main system is also important. Stress is not the direct causal effect but in many cases a strong contributor. Much like any animal, continued stress reduces the natural immune response allowing health problems to arise. Overstocking, cramping/stunting, overfeeding, improper foods, fish aggression, poor water chemistry and the hobbyist themselves are all contributors. In other words, keep your hands out of the tank unless it’s necessary. Only by maintaining a stress free environment can a fish live a long and healthy captive life.

In regards to true fungal infections (Saprolegnia sp.), the resulting correction of underlying conditions is still the first best step. The same appearance from wounds, spores or water molds if you will are the main contributors. It can also be identified in the absence of a wound by scales standing on end surrounded by white or grey cottony tufts (not to be confused with Uronema marina).

Where the infection is quite advanced or tank mates are taking advantage of the fish’s weakened condition, it is best to place the fish in a [url=]quarantine[/url] tank where it can recoup unhindered. Be sure to transfer the fish without the use of a net. Corralling the fish into a container will prevent further damage and possible harm to other areas. It is important to note that most bacterial infections in marine animals are gram negative in nature so not just any medication will do. If advanced, treat with Maracyn II® at double the recommended dose daily for seven days is the best suggestion. Furacyn® or other nitrofurazone based medications are also effective. Slowly reducing the salinity each day towards the 16-18 ppt range will help reduce stress in the fish and aid in keeping up the appetite which is usually curbed by such ailments as well as lethargy. Lowered salinity will also help in the loss of vital fluids through reduced osmotic pressure.

Upon the successful treatment of the infection, it is best to keep the fish in quarantine until fully recovered. Be sure to bring the salinity back to the same as the main system much much slower than it was lowered. Fish can tolerate drops in salinity much easier than it can be raised so be sure to increase no more than 0.001/day.

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