We've gone over how to do a freshwater dip and how to set up a hospital tank. But what about the meat and potatoes? What does a sick fish look like? What diseases do fish get, and how do we get rid of them?
A sick fish displays obvious changes in normal behavior. Erratic swimming patterns, listless behavior, lying on its side, dull or pale color, loss of appetite, rapid breathing, and white, fluffy patches on skin, gills, or body, all of these are signs of a sick fish. The earlier you spot the symptoms, the better a chance you have of successfully treating and healing your fish!
Why do fish get sick?
Stress. Simple as that. Stress weakens the immune system making the fish more susceptible to disease. Stress comes in many forms including:
1. Shipping and transport.
2. Introduction to a new tank.
3. Poor water quality or sudden changes in water parameters (salinity, pH, temperature, calcium, alkalinity, ammonia, nitrites, nitrates).
4. Poor nutrition (not feeding enough or the right kind of food).
5. Boistorous, aggressive tankmates.
6. Poor enivronment, e.g. tank too small to meet space requirements of fish.
Common Fish Illnesses:
1. Cryptocaryon irritans (Ich)
This is an obligate parasite (meaning it cannot survive without its host) with a complex life cycle often introduced from new fish, coral, or live rock. ) (It's actually a ciliated protozoan). Tangs and surgeonfish are particularly susceptible. Death can result in a few days.
2. Marine Velvet (Amyloodinium ocellatum).
Symptoms are similar to ich but instead of punctate white spots, the fish has more of a white powder covering its body, almost like its been dipped in powdered sugar. Caused by a parasitic algae (actually a dinoflagellate). Symptoms start off with labored breathing. Powdered spots occur later. Because it attacks the gills first, marine velvet is more serious than ich. By the time you see it, it may be too late. In addition to powdered spots and labored breathing, swimming may also be erratic. Fish may also rub against rocks and gravel. Death can occur within two days of symptoms. Hyposalinity is not effective for this parasite. Cholorquine diphosphate (also used to treat malaria!) is a good treatment (5-10 mg/l for 10 days). Metronizazole will also treat dinoflagellate infections. Copper, formalin, and freshwater dips are also common treatments. As always, these chemicals are toxic invertebrates, micro-/macro-algae, and nitrifying bacteria.
3. Black Ich (Turbellarian)
Also called Tang or Surgeonfish disease because it is often seen on Yellow Tangs. Like ich but black spots instead of white. This disease is actually caused by turbellarian flatworms from Paravortex genus. This disease is not as quick-killing as Ich or Marine Velvet but needs to be treated to prevent secondary bacterial infections from occuring. Treat with freshwater dip followed by formalin bath and recovery in QT tank.
4. Brooklynella (Clownfish Disease)Worst of the parasites. Often seen in wild-caught clownfish. This is a cilliated protozoan that can reproduce asexually, spreading much faster than Ich or Marine Velvet. Attacks gills first, which makes breathing difficult. First symptoms include rapid/labored breathing, thick, excess mucous secretion, color dulling. Lethargy, loss of appetite, cloudy eyes also occurs. Toxins secreted from protozoa cause open ulcers gills and skin. Death can occur in 12 hours if not treated immediately. Remove to QT tank and perform daily baths in formalin. Other treatments, like hyposalinity, freshwater dips, or copper, are not effective.
1. Fin Rot
4. Fish Tuberculosis
Flukes and Parasitic Copepods: