Colin, how often have you encountered TB in fish? let me answer that question NONE, so stop with the possiable TB diagnosis.
Tuberculosis (TB) is commonly found in shops and importer's aquariums/ quarantine facilities all around the world.
Between 2004-2006 I had fish dying and had them necropsied by a number of Vets (including 2 fish vets) and they all confirmed TB. I spent a couple of years researching and trying to find a way to cure the fish but ended up killing them all and scrapping the tanks. I had over 600 adult fish (worth in excess of $18000) that were used for breeding stock and supplied fish to various shops, so trying to find a cure was worth it.
During my research I contacted most of the pet shops and importers in Australia and they all confirmed their tanks had TB or were suspected of having TB on at least one occasion during the last 2 years. Normally the contaminated tanks were just flushed out and the fish were destroyed. Some places destroyed the fish and disinfected the tanks and contents with chlorine.
A number of the importers informed me that they had been told by their Asian suppliers, that certain fish had been shipped out of Asia and the fish were known to carry TB. There were apparently several fish farms in Asia that were knowingly sending out fish that were infected with TB.
I spent time working with the vets that I contacted about this and they confirmed that pet shops and private fish keepers had brought in fish over the last few years that had been confirmed as having TB.
I had contact with people in the US that did some research into this and they were informed by shops that TB was sometimes found in batches of fish that had come in.
I also had contact with Fisheries WA and they confirmed several aquaculture facilities in Western Australia (including a government run facility) had TB in their systems and they were releasing diseased fish into the wild for recreational fishing.
So Tuberculosis is very real and quite common and the original posting said that 2 fish had died from similar symptoms, 12 months apart. This fits a TB infection with the Mycobacterium being slow growing and taking a year or so to build up in sufficient numbers before it destroys an internal organ and subsequently kills the fish.
Mycobacteria are a very old genus of bacteria that have a waxy coating surrounding their cells. This makes them extremely difficult to kill and the cells can survive in dry environments for years, and damp environments for even longer. One of the vets I worked with had done research into fish TB and found dormant but live Mycobacterium cells in a dry river bed under a rock. There had been no water in this river for 8 years and the TB cells were alive and became active and started dividing when put into a petri dish and cultured.
So flushing a tank out does not guarantee getting rid of the Mycobacteria and if a new fish is introduced into that tank, it could easily pick up the TB cells and develop an infection that kills the fish between 6 months and 3 years after it is infected. Bigger fish survive longer because the Mycobacteria have to build up in numbers before they destroy an organ. And fish in cool water survive longer because the Mycobacteria don't grow as quickly in cool conditions.
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I am wondering if I am reading this correctly.. you are recommending to do a 100% water change and redose antibiotics everyday?
Most antibiotics recommend not doing water changes at all while using. It will state how much to change if it is needed.
Just trying to understand your recommendations, also wondering why you would recommend that..
Also Tuberculosis is very very rare. I wouldn’t even suggest that as a diagnosis.
Most anti-biotics break down quickly in water and become useless after a short period of time. However, bacteria produce a slime/ biofilm that can protect them from anti-biotics and other medications. Cleaning the tank out each day and retreating at a full dose helps to ensure the anti-biotics work on the fish in the water and don't get wasted on other types of harmless bacteria that set up home in the tank after the anti-biotics have broken down.
In addition to this if you use anti-biotics in a tank with a filter, the beneficial filter bacteria are killed along with the ones harming the fish and you end up with ammonia building up in the water. The ammonia poisons the fish and puts them under more stress.
Anti-biotics and most other medications reduce the oxygen levels in the water. This combined with ammonia from the fish, dead filter bacteria and the dead microscopic organisms in the biofilm, stress hormones released by the fish because they are sick or being exposed to anti-biotics, all contribute to the water becoming pretty unsuitable for fish to live in. Changing all the water before retreating the tank will remove all the harmful chemicals and any residual anti-biotics leaving a clean tank ready for treating. There will be no chance of overdosing because there won't be any anti-biotics in the new water. The clean water and clean tank are beneficial to the fish's overall health and anti-biotics work best in a clean environment.
