Snout Rot

By: | Date: 06/25/2004 | 2 Comments |
Seahorse showing signs of snout rot at the tip of snout.

Seahorse showing signs of snout rot at the tip of snout.

The purpose of this guide is to provide a reference, or starting point, in identifying and treating some of the most common diseases and medical conditions of seahorses in home aquariums. It is not, however, set in stone; constant scientific research and anecdotal evidence cause the seahorse hobby to evolve every day, furthering our understanding of these diseases and conditions, how they manifest themselves in our fish, and how we can best treat them. This guide should be used responsibly and not as a sole reference. If ever presented with diseases in your seahorses, use this guide first, but always trust your own knowledge and common sense when treating your seahorses.


Snout rot is the erosion of the skin around the snout of a seahorse. Similar to and likey caused by the same pathogen as flesh-eating bacteria, Vibrio spp., snout rot can often be controlled with pre-treatment before the seahorse is released into the display aquarium. The disease may be cause either by fungal infection (in which case the snout will be pinkish) or bacterial infection (in which case the snout will be white). If left untreated, the disease will often appear when water quality worsens or during prolonged periods of stress.


  • discoloration of the snout
  • swelling of the snout
  • lockjaw
  • loss of appetite
  • tissue erosion on the snout

When first infected, seahorses generally are not bothered by snout rot. As this grave disease progresses, however, the mouthparts of an infected seahorse may become so destroyed that eating is no longer possible. This causes inevitable death.

Seahorse on left with snout rot, compared to healthy individual on right.

Seahorse on left with snout rot, compared to healthy individual on right.


As with flesh-eating bacteria, the best treatment for snout rot is preventative quarantine before release into the display tank. The disease will not always manifest itself immediately, however. Luckily, treatment is not very difficult.

The best treatment is by use of combination medications such as Paragon II in a hospital tank (editors note: the company that makes paragon II is no longer in business. Paragon II contained:  Metronidazole, neomycin sulphate, furazolidone, naladixic acid, and sodium chloride. Neo3 is a good alternative that targets just the bacteria causing the problem). This medication covers gram+ bacteria, gram- bacteria, and fungus. It has ingredients that can eliminate or stop the progression of snout rot within days. In severe cases, a double treatment may be necessary. In any case, follow the directions of the manufacturer. Topical treatments such as neomycin (Neosporin) and iodine or formalin solutions (1 cup water to 15 drops of either or both) used three to four times daily on the affected area can also help in controlling the progression of the disease.

If after treatment the disease returns, the infected horses will need to be requarantined, the display tank may have to be scrubbed down, and all equipment may have to be sterilized with bleach. Be careful not to allow any sterilization chemicals to make their way back into the aquarium as this will destroy the essential denitrifying bacteria present in the aquarium’s bacterial filter bed. If this does not arrest the occurrence of snout rot, the seahorses may have to be relocated to a new display system. This is often, however, not the case.

Please be aware that pathogens affecting seahorses are living beings that can adapt and become resistant to treatments if performed incorrectly. When using antibiotics and other medications, be sure to follow the manufacturer’s instructions completely and through the entire suggested treatment period. Due to the adaptive nature of bacteria and other pathogens, failure to do so can cause the evolution of strains resistant to current treatments.  If necessary, seek the assistance of a veterinarian to ensure that no treatment is left unfinished.

2 Responses to “Snout Rot”

  1. MelMegan Says:

    Even them got their own medication and diseases? At least now its not a problem anymore since research already found out how to manifest and identify the snout rot.

  2. Maria Says:

    I have a seahorse that I believe has this how do I apply the medication on him/her? Please advise.

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