Clamped Fins

A guppy has clamped fins that it holds close to its body, and its caudal find is folded. It hangs near the surface, relatively immobile. It may shimmy or swim somewhat erratically.
These are signs not of a disease but rather they are symptoms of a number of diseases (particularly Clamped Fin Disease or Gyrodactylus). These are also symptoms of poor water quality. In the absence of any other evidence of illness, the problem is probably poor water conditions.

Symptoms and Behavioral Signs
The following symptoms may selectively appear on guppies suffering poor water conditions:

•    Fins clamped
•    Guppy shimmies
•    Fish is shy or hiding
•    Fish lack appetite
•    Fish is still or inactive

The guppies are under a great deal of stress and the weakest guppies in a tank might already be succumbing to a variety of diseases. Note that shimmying is a behavioral sign associated with other diseases, like columnaris.

Causative Condition
High ammonia, nitrite or nitrate levels in the tank. Low oxygen levels. High level of organic waste in the tank. pH levels out of range (less than 7.0 or more than 8.4) or a recent sudden change in the pH, temperature or hardness levels. If the problem is confined to one or several tanks, the chances are that the nitrogen cycle is out of whack in those selected tanks. This may be due to overfeeding or to a mechanical failure in the filtration system.

Diagnosis
If the fish are scratching or flashing it is an indication of irritation of their skin, and could be due to parasites. If the fish are swimming erratically, it is probably a parasitic disease. See library entries for Chilodonea, Costia, Skin Flukes (gyrodactylus), White Spot (Ich) and Velvet Disease

Examine the fish for any other signs of abnormalities or disease. If clamped fins are the only symptom, then it is probable water conditions are bad. If they are hanging near the surface, and there is not other signs of disease, than it is probably poor water quality.

Look on the bottom of the tank. Do you see a lot of mulm compared to other tanks? Is there uneaten food on the bottom? Is the water cloudy? Are the filters clogged? These are signs of overfeeding or the failure of the nitrogen cycle.

Check your food supply. Does it smell bad?

Check the water parameters. If the chemistry in your tank is not suitable for guppies, correct the situation, following the steps outlined in the next section.

Prevention and Treatment
When feeding, culling or showing your fish, develop the habit of giving all the inhabitants of a tank a quick visual inspection. If you see a guppy in a corner or hovering near the surface, with clamped fins, you may have water parameter problems. It's best to catch water quality problems quickly, as they soon lead to an outbreak of disease. If the affected guppy looks lethargic or firmly clamped, consider removing it to a hospitable tank.

If the water tests showed that the chemistry of the tank is out of balance, use one of many detoxifying liquids available to neutralize such problems as high ammonia levels. Do a 30% water change, using properly conditioned water. Be careful to not contaminate other tanks. If a major portion of the tank inhabitants are showing signs of stress, consider moving them to another conditioned tank, or changing 50% of the water with conditioned water.

Follow-up for three or fours days with a siphon of the bottom of the tank and a 10% daily water change.

If the problem is overfeeding, give the guppies a two day holiday from food and resume feeding with substantially reduced quantities.

Resist medicating your guppies unless you are sure that the problem is disease. Many medications damage the nitrogen cycle, exacerbating the problem. There is a Medications Affecting the Nitrogen Cycle article in the wiki.

One or two treatments with potassium permanganate (PP) should not adversely affect the nitrogen cycle: If you suspect overfeeding, use PP to reduce the organic pollutants in the tank. Before treating, clean the filter and do a 30% water change. Then dose the tank with PP, using our 5 ppm level indicated in the Potassium Permanganate entry.