Is white stringy poop in fish a sign of a digestive problem?

Enteritis, also called bacterial enteritis or rotten-gut plague, is a digestive tract infectious disease of many kinds of fish caused by Aeromonas punctata. It is mainly triggered by eating unclean feed, overeating, a bloated and distended intestine, blocked excretion or water pollution; when these lower the fish's disease resistance, the bacterium multiplies in large numbers in the intestine and can cause an outbreak. Among ornamental fish, goldfish, discus, guppies, koi and flowerhorn cichlids have all had cases of infection. When the water temperature is above 18°C, the disease begins to spread; when the water temperature is 25-30°C, it is at its peak.

I. Pathogen

The pathogen of enteritis is Aeromonas punctata. It is Gram-negative, and after 1-2 days of culture on agar medium the colonies produce brown pigment and are semi-transparent. Its optimum growth temperature is 25°C, and it can be killed above 60°C; but if the aquarium water were above 60 degrees, you could basically sprinkle on some salt and have boiled fish.

II. Main symptoms

Sick fish appear dull, move slowly, stay away from the group and lose appetite; the body darkens, most noticeably on the head and tail fin. In the late stage, the fish floats at the surface with its head up and tail down, the abdomen becomes distended, the anus becomes red, swollen and protruding, and there is diarrhea with white feces; in severe cases the fin bases become congested and red patches appear on the abdomen. When the belly is cut open, fluid is seen in the abdominal cavity and the intestinal wall is congested and inflamed; in mild cases only part of the intestine turns red, while in severe cases the whole intestine turns purplish red, with no food in the gut but filled with pale yellow mucus and bloody pus.

III. How is enteritis diagnosed?

This disease has characteristic features. A preliminary diagnosis can be made based on congestion and redness of the fish's intestine, especially obvious in the posterior intestine, a red, swollen and protruding anus, and a lot of pale yellow mucus in the intestinal cavity.

IV. Preventive measures

1. Strengthen feeding management

A large change in the amount of feed given, a sudden change of feed variety, reduced oxygen in the water, water pollution, moving the fish after it has eaten its fill, and feeding unclean feed can all bring on enteritis. Therefore, feeding clean feed, giving small amounts over several meals, sticking to fixed quantity, fixed quality, fixed location and fixed timing, promptly removing fish feces and leftover feed, regularly disinfecting the water, keeping the water clean and increasing dissolved oxygen all play an important role in preventing this disease.

2. Regular preventive medication

In the seasons of early spring and late autumn each year, when the temperature changes greatly, feed food soaked in water with norfloxacin or allicin once each.

V. Treatment

When enteritis is found in fish, treat it with a combination of oral and external methods.

(1) The affected fish should be fasted for 1-2 days, the water temperature kept unchanged, and the water changed once a day to keep the water clean,

or the affected fish should be kept separately.

(2) Use an external medicine to disinfect the water body; generally broadcast bleaching powder over the whole pond at 1 gram per cubic meter of water to purify the water.

(3) Use oral medicine to kill the pathogen in the fish; norfloxacin, allicin and the like can be mixed into bait or used to soak bait and then fed.

(4) If the fish can no longer eat, a medicated bath can be given. For the bath, use gentamicin, oxytetracycline and so on. Gentamicin, kanamycin or penicillin can also be injected into the muscle or abdominal cavity for treatment.

VI. Points to note in diagnosis and treatment

A preliminary diagnosis can be made based on the symptoms and how the disease is spreading, but care must be taken to distinguish it from the following diseases.

(1) Food poisoning

In fish with food poisoning, while the intestinal wall is congested, there is a large amount of food in the intestine, and fish eating the same feed suddenly die in large numbers.

(2) Red-skin disease

In red-skin disease the intestine is sometimes also congested and inflamed, but the main symptoms are on the body surface: part or most of the skin on the body surface becomes inflamed and bleeds, and scales fall off. In fish with simple enteritis, the skin and scales remain intact.

I hope the above can help everyone, and if there is anything lacking, I welcome your guidance.