Praecox rainbows still sick. Help

The fish have ulcers, which are usually caused by Tuberculosis (TB).

If you are feeding them frozen bloodworms, stop feeding it to them.

Make sure the fish get plant matter in their diet every day. Duckweed is a floating plant that grows readily and is eaten by most rainbowfish. Algae and fine leaf plants like Ambulia can be cut up and offered to them.

Use a goldfish flake and a vege flake, and feed a variety of frozen (but defrosted foods like prawn/ shrimp, daphnia, brineshrimp.

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You can try treating them with an anti-biotic to kill the bacteria causing the ulcer, but you can't treat TB. So if it is TB, then the fish will eventually die. If you do use anti-biotics, try to find a food with anti-biotics in because it works better and doesn't wipe out the filter. If you have to use anti-biotics then monitor the ammonia and nitrite levels during and after treatment.

Make sure you wash your hands with warm soapy water after working in the tank. Avoid putting your hands in the tank if you have cuts or scratched on them. Avoid getting aquarium water on open wounds.

If the fish have TB the bacteria will be in the tank and can get into wounds on your skin and cause a localised infection called a granuloma. If you get any sores that don't heal, see a doctor and tell them your fish might have Tuberculosis. Get the doctor to tab swabs of the sores and send them off for analysis. Wait for the results before taking medication. There are different strains of TB and they are immune to different anti-biotics. Most doctors automatically stick you on anti-biotics without finding out what strain is causing the infection and this can make the problem worse. So get swabs sent off for testing and wait until you know what strain it is before taking medication to treat it.

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If it is TB, it will remain in the tank until you kill everything in the tank and disinfect everything with straight bleach or heat (60C for several minutes).

Most people who have TB in their tanks just leave the tank to run and when everything has died they scrap it, disinfect everything, and start again.

 

Rainbowfish in Australia are regularly infected with TB. There are also regular outbreaks in the US and Europe. In most cases, the first sign is ulcers that appear on the side of the body.

Reducing the amount of bloodworms in their diet, and increasing the amount of plant matter usually makes a big improvement in their health. Big (75%) water changes and gravel cleaning done each week also helps.

Keeping the temperature around 24C helps them live with it for longer because the Mycobacteria (TB) grow slower in cooler water.

There are lots of fish from around the world that evolved in areas with fish TB. Barbs, danios, loaches and catfish, seem to be tolerant of it, but rainbowfish never evolved with it and have no resistance to it, which is why they tend to show it and lots of other fish don't.

The only way to confirm TB 100% is to have a sick fish necropsied by a vet. If you monitor the fish over the next 12 months and they suddenly die one here and one there, and their symptoms include suddenly bloating up (getting fat over night), breathing heavily near the surface or by a filter outlet, not eating, going pale, doing a stringy white poop, and dying within 24 hours of showing these symptoms, then it's probably TB.

 

The fish either had it before you got it or the TB cells were introduced with something from a contaminated tank. Normally it comes in with the fish. I had rainbowfish that lived for 2 or 3 years before they died from it so the fish probably had it before you got them.

Mycobacteria are very slow growing and take months or even years to build up in large numbers and harm the fish. Most other types of bacteria double their numbers every couple of hours but TB might double in numbers every day or two, even longer in cool water.

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Increase the plant matter in their diet. Grow duckweed on the surface and feed algae and plant based foods like goldfish food. Increasing the amount of plant matter makes a huge difference to the health of rainbowfish.

Clean the filter every 2 weeks. Wash filter media in a bucket of tank water.

Try to gravel clean the substrate regularly because the TB cells that are expelled from the fish, will sink to the substrate.

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Monitor the ammonia and nitrite levels when treating with the Interpet bacterial medication and do big water changes if you get any readings.

 

Goldfish foods have more plant matter and less meat and it helps with fish that naturally eat a lot of plant matter. Goldfish flakes and Vege flakes are both suitable for rainbowfish.

 

Use whatever you can get. Myxazin may or may not work but it's safe for cories.