Tuesday, February 14, 2012

Tropical Fish Diseases

Useful FISH HEALTH information for tropical fish hobbyists:

Probably one of the most common questions I get asked is “What’s wrong with my fish?” Well, that’s a little hard to diagnose without actually seeing the fish itself, but there are some common ailments you should be familiar with, and you should be able to identify when something is really wrong.
First off, you need to have a “Fishy First Aid Kit” handy.

Yes, you can have a first aid kit for your fish. My advice is to set one up before something goes wrong.
  • Water quality test kits: pH, ammonia, nitrite, nitrate
  • Aquarium salt (NOT table salt. Most table salts contain additives to keep them from clumping. Kosher or rock salt is OK).
  • Malachite green/formalin ich remedy
  • Methylene blue
  • Chlorine bleach for disinfection
  • Maybe one antibiotic (Kaynamycin or Furanace)
  • Antibiotic-containing food
  • Copper remedy for parasites 
And for fish big enough to handle:
  • Q-tips
  • Malachite green or mercurochrome
Now that you have all those emergency items on hand, here are a few basics to watch out for that are indications your fish may be in trouble.
Most important: watch your fish and know what their normal behavior and appearance is. If you don't know what normal is, you can't possibly know what sick looks like.

  • Clamped fins (fins are held abnormally close to body)
  • The fish refuses its usual food for more than 2 days.
  • There are visible spots, lesions, or white patches on the fish.
  • The fish gasps at the surface of the water.
  • The fish floats, sinks, whirls, or swims sideways.
  • The fish shimmies (moves from side to side without going forward).
  • A normally active fish is still.
  • A normally still fish is very active.
  • The fish suddenly bloats up, and it's not due to eggs or young.
  • The fish is scratching against tank decorations.  

Symptoms: Your fish are gasping at the surface, or swimming lethargically, or even changing color – from bright to dark or dull. There are no visible lesions you can see, but they may be swimming with fins clamped. Many fish of different species are affected, and possibly the whole tank. 
If the water has been bad for a while, the fish may have finrot, or streaks of blood in their fins.
  • If fish are gasping at the surface, or have purple gills: high ammonia or low dissolved O2 may be the problem; test ammonia, dissolved O2
  • If the main symptom is inactivity: test nitrites, pH, dissolved 02, nitrates
Depending on your test results, try the following: 

Change enough of the water to reduce ammonia levels to 1-2 ppm for freshwater or below 1 ppm for saltwater. If that means changing more than a third of the water, be sure the water you add is the same temperature, salinity, hardness and pH of the tank water. 

It is also okay to do multiple smaller water changes for a few days. Aerate, and make sure pH is at or below 7.0 for freshwater tanks. In addition to or instead of changing water, you can also add a dose of AmQuel to give fish immediate relief. Find out why ammonia is present and correct the problem. 

Change enough of the water to bring nitrites down to below 2 ppm (as with ammonia, if this is a lot of water, do multiple water changes), add 1 tbsp/gallon salt (not all fish may tolerate this much -- start out with 1 tsp), and add supplemental aeration. Find out why the nitrite levels are high and correct the problem. 

Change water and clean the filter. If your filter is dirty, there is more waste material present to break down into nitrate. Start feeding less and changing water more often. 

Low oxygen
Run an airstone. If this helps a lot, the fish probably don't have enough oxygen in the water. Your tank may need cleaning, fewer fish, or additional water movement at the surface from a power head, airstone, or filter. 

Improper pH
If pH is too low: make sure carbonate buffering is adequate -- at least 5dKH. In general, adding baking soda at 1 tsp. per 30 gal. raises dKH about 2 degrees. For a 10-20g tank that just needs the pH a little higher, try about a quarter teaspoon. If that isn't enough, add up to a teaspoonful more. You can scale this up to 1 tsp/30 gal for larger tanks. If the pH is still too low and the KH is at least 5-6 dKH, clean the tank. 

For long-term buffering in saltwater and alkaline freshwater systems, add crushed coral. If pH is too high, pH down (phosphoric acid) can be added. Don't rely on this stuff, except in extreme situations like ammonia poisoning because it can cause excessive algal growth. To lower pH long-term, filter over peat, or use distilled or deionized water mixed with your tap water. 

Symptoms: Fish look like they have little white salt grains on them and may scratch against objects in the tank. 

White spot disease (Ichthyopthirius multifiliis) is caused by a tiny organism that starts with one fish, falls off and attaches itself to the tank glass or gravel, then grabs onto another fish and spreads to the entire tank.

To treat it, you must treat the entire tank. Medicine must be added to the tank to kill the parasites – but be careful – if it’s a reef tank, invertebrates are very sensitive to reef medications, so really the only alternative is to remove the fish to a quarantine tank.

Some people think that ich is probably dormant in most tanks, and is probably triggered by temperature fluctuations. 

Remedy: For most fish, use a medication with formalin and malachite green. These are the active ingredients in many ich medications at fish shops. Some commercial products are Kordon's Rid Ich and Aquarium Products' Quick Cure. Use these products as directed (usually a daily dose) until all of the fish are spot-free. Then dose every three days for a total of four more doses. 


Fishes' fins turn whitish and die back. Fin rot often follows damage or injury. It can also be caused by poor water quality. 

Remedy: First, fix the water and remove any aggressive species that are biting your other fish. Change about 25% of the tank water and add 1 tsp/gallon salt to promote healing. Healing should begin within a couple of days. 

If it worsens, it could be fungal or bacterial. 

Fungal finrot looks like clumps of cotton on the fins and usually follows injury. Treatment for fungus: For fish large enough to handle, catch the fish, and dab malachite green directly on the fungus with a Q-tip. This is extremely effective. Repeat treatments may be necessary.

For smaller fish, try a commercial product such as Maroxy. For severe infestations, try a bath in methylene blue (enough so you can barely see the fish) until the fungus turns blue or for about 20 min. Don’t add methylene blue directly to the tank; or you’ll kill your plants and ruin the biological filter. 
Bacterial finrot is whitish, but not cottony and can be contagious. The fish then need to be removed from the tank and medicated. 

Treatment for a bacterial infection: Remove the fish to a quarantine tank and treat with Antibiotics. This is stressful for the fish, and doesn't always work, so be sure of what you’re doing before you try this. If the fish is still eating, try an antibiotic food. 

If the fish is not eating, a bath treatment is necessary. A combination of Kaynamycin and Furanace usually works, especially for Columnaris. Remove to a separate tank and aerate heavily.

Sometime fistfights will break out in your tank among species, and the combatants may sustain injuries that are severe enough to bleed. Other fish may run into tank decorations, walls, or rocks. 

Larger fish can be netted and their injuries dabbed with mercurochrome (available at drug stores) or Betadine (iodine-based antibiotic also available at drug stores) to help prevent infection. Do Not Get These Chemicals in the gills and eyes! 

For really small fish, put the affected fish in dilute methylene blue (pale blue) and 1 tsp/gallon salt in a separate tank. 

Watch the fish to be sure injuries are healing cleanly, and repeat the mercurochrome dosage if necessary. If finrot or fungus sets in, see the above section on finrot.

This is what makes fish swell up like a balloon and their eyes bug out. Dropsy can be caused by a variety of things – the most common are high nitrates in the tank and bacterial infections. The swelling is caused by the fish is absorbing water faster than it can eliminate it,

Your fish may recover with no treatment whatsoever, or may die despite your best efforts to save it.
If there are no water quality problems, you may want to attempt antibiotic treatment in a separate tank. 

This disease can affect discus, other cichlids, and many saltwater fish. The fish develops holes in its head and sometimes along its lateral line. The causes are unclear but as in any disease, stress and poor water quality likely play a role. 

It’s interesting to note that fish in planted tanks rarely get HLLE, which supports the nutrition idea, since fish can nibble on the plants and obtain extra nutrition. Or it may have something to do with the interchange of plants and oxygen. Scientists just aren’t sure.

Remedy: First, make sure water quality is optimal and reduce stress. Carbon filtration may facilitate this problem, since it can remove nutrients from the water. So if you are using carbon filtration, switch to another form for a while, and feed a vitamin-enriched food in the meantime, paying particular attention to vitamin C supplementation.

For stubborn cases, some experts suggest metronidazole (Flagyl) to eliminate Hexamita (a mildly pathogenic protozoan) from the lesions.

Fish floats upside-down or sideways. This is particularly common in fancy goldfish because of their bizarre body shapes. Dry food eaten quickly swells up in the fish's intestine and keeps the fish from controlling its swim bladder properly. This is a little like bloat in a dog, if you’re familiar with that malady.
To help, feed the fish pre-soaked or gel-based foods. Green foods are also helpful. 
As with finrot, these disorders can also be caused by bacterial infection. Treatment is much the same. Use antibiotic food if the fish is eating, or add antibiotic to the water in a quarantine tank if the fish is too sick to eat. 

Add a copper remedy to the tank and monitor it with a copper test kit. Also, Mardel's Maroxy works well. For anchor worms or leeches on pond fish, remove them from the affected fish with tweezers and swab the area with mercurochrome to prevent infection. 

Fish look like they have been finely dusted with flecks of gold. Fins may be clamped and the fish may shimmy. 

Treat with an anti-parasitic medication such as copper or formalin/malachite green.