From The Aquarium Wiki
What is Fin Rot (or Tail or Gill Rot)?
Finrot is a common bacterial disease of fish kept in low quality water conditions.
It is caused by gram negative bacteria like Aeromonas, Pseudomonas, or Vibrio which eats the delicate membranes of fish. Usually the area of the damaged fin becomes opaque and white then is eaten away by the bacteria. Often fungus develops giving the wound a fluffy appearance. It is easily treated and the fin will grow back if not too badly damaged.
- Tail Rot is named thus as it it appears initially in the tail (caudal) region
- Gill Rot is named thus as it it appears initially in the Gill region as white patches.
- If not treated the fish will usually die.
This serious bacteria can causes fin/tail/gill rot as well. If the usual bacterial treatments prove not to work then your animal may be infected with Mycobacteriosis.
- Bad water - regular changing of the tank water and lowering of wasted fish food will prevent the levels of bacteria from climbing.
- Fin damage due to overcrowding, handling, other fish.
- Regular water changes can often cure this if it's not too advanced.
- Adding a level of salt to the water is a good mild treatment if the species of fish can tolerant it.
- Antibiotics (not available in Europe over the counter) are an option for advanced cases. Chloramphenical, Oxytetracycline, and Tetracycline for example.
- Fitting a UV device to the tank will help keep the levels of bacteria down.
- Fin Rot & Fungus Control (contains 2-Phenoxyethanol 5.66 %w/w) 
- Disease Clear (contains Protargol 0.151%w/w (Silver proteinate) )
- Bacteria Control (contains Formaldehyde (35.6 % solution) 10.92 % w/w, Sodium Chloride 0.60 %w/w, Magnesium Sulphate 0.30 %w/w % Allantoin 0.04 %w/w) 
- No.8 - Anti Fungus and Fin Rot
- No.10 - Methylene Blue
- Myxazin - broad spectrum bactericide (contains Formaldehyde 0.12%w/w, Malachite Green 0.085% w/w, Acriflavine Hydrochloride 0.055% w/w) 
- E.M. Erythromycin™ Powder - Broad spectrum Antibiotic. (contains Sodium chloride >80%, erythromycin phosphate 1-10%, Amorphous silica 1-5%. See MSDS)
- Furan-2™ Powder - Kills gram-positive & gram-negative bacteria (contains Sodium chloride >90%, Nitrofurazone 1-5%, silica amorphous 1-5%, furazolidone < 1%. See MSDS)
- Melafix® (contains Melaleuca, as Cajuput oil 1%. See MSDS)
- PimaFix™ Anti Fungal & Bacterial (contains bay oil 1%. See MSDS)
- T.C. Tetracycline™ Powder - Kills gram-negative bacteria (contains Sodium chloride >60%, tetracycline hydrochloride 10-30%, amorphous silica 1-5%. See MSDS)
- Triple Sulfa™ Powder three sulfa antibacterial medications (contains Sodium chloride >60%, sulfathiazole 10-30%, sulfamethazine 1-10%, sulfacetamide sodium 1-10%, amorphous silica 1-5%. See MSDS)
- TetraMedica GeneralTonic Kills bacteria, fungus and parasites.
- Lifeguard™ All-in-One - Kills bacteria, fungus and parasites.
Jungle Labs (USA)
- Lifeguard - All-in-One - Kills bacteria, fungus and parasites (contains HaloShield (1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone))
- Anti-Bacteria Medicated Fish Food - for bacterial Infections (Mouth rot)
- Binox (Crystal) Broad range anti-bacterial and Fungus treatment contains Nitrofurazone <9%. See MSDS)
- TRICIDE-Neo™ - Antibacterial Dip - a concentrate of NeoMycin antibiotic 
- ↑ 1.0 1.1 1.2 1.3 Veterinary Medicines Marketed under the Small Animal Exemption Scheme, VMD
- ↑ 2.0 2.1 Chemical information on the product
- ↑ Tricide Neo tris-EDTA Solution Against Bacterial Infections
- Fitting a UV device to the tank will help to keep the levels of bacteria down.
- Setting up a tank with a natural soil-based substrate will suppress the levels of this bacteria down. See Walstad.