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| Sick Tilapia http://byap.backyardmagazines.com/forum/viewtopic.php?f=29&t=14084 |
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| Author: | Islandtimebrah [ Nov 7th, '12, 06:27 ] | ||
| Post subject: | Sick Tilapia | ||
Hi there, This is my first post but I need help because I have sick fish. I found the tilapia in the picture swimming around in circles at the top of my tank. I have 2 16,000 gallon systems, and fish in both systems are showing these growths at the base of their fins. I'm not sure what it is but I'm worried about my fish! Has anyone seen this before? Does anyone know what this is?
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| Author: | slowRider [ Nov 7th, '12, 07:53 ] |
| Post subject: | Re: Sick Tilapia |
Sounds like Streptococcus. Its bacterial, so salt might fix it. Good luck with that. Hate to see fish losses  Some info: http://www.fao.org/docrep/008/v9551e/V9551E04.htm |
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| Author: | bunson [ Nov 7th, '12, 08:22 ] |
| Post subject: | Re: Sick Tilapia |
Most lesions/ulcers on fish are caused by parasites, bacteria or a fungal infection. How/when did the ulcers start? The fish look relatively large so I am going to guess they were growing OK in the system for a while, so what changed or what was added which caused these ulcers? Did you add some more fish, without quarantining them for a few weeks first? Have you got a contaminated batch of feed? Have you changed your water source? Could a contaminant have entered during any regular maintenance (usually though poor hygiene of the people doing the work)? This practices below are normally for aquaria and backyard systems and may not necessarily scale up to systems like yours. You might have to wait for some of the commercial-size system owners to chime in, but until that time... To deal with infections in "small" AP system as a whole, salt the water to 8-10ppt (8kg-10kg of pool salt per 1000L water, 480kg-600kg per 60,000L in your case !! ) and maintain this concentration for a few days. Some people advocate adding the salt all in one big hit to "shock" the parasites/bacteria, but I don't think it really matters so long as all the salt is added within a relatively short timeframe (few hours). I dissolve all the salt before adding it to the tank as if a fish touches raw salt, it can burn them, but some people don't worry about doing this. Pump continuously and add extra air if you have it. After a few days, or when you notice the symptoms have improved, you can reduce the salinity to 1-3ppt by adding fresh water, and maintain this level infinitum for their general well-being and to inhibit fungal growths. If after a few days there is no improvement, drain up to 50% of the system water and replace this with fresh water salted to the same concentration, repeat every couple of days until improvement is seen. If you need to deal with the sickest individual fish, create a hospital tank, making sure to add plenty of air, and salt up to 20-35ppt (20kg-35kg salt per 1000L) and place the fish in this brine for an hour. If you have a lot of very sick fish, change the water and re-salt for each batch. If you've got too many sick fish and they're too far gone for rescue, euthanase them to prevent them spreading their ails to the remaining fish. If you have any salt sensitive plants which you want to keep, remove them beforehand. Most plants can survive the system salting level, from my experience, strawberries do not tolerate salt above 3ppt. Just like our immune systems, fish immune systems get run down faster when under stress, so remove/minimise any stressors for your fish. Don't keep peering into the tank for a casual peruse, stop any visits to the tank by any curious children/visitors etc, only visit the tank to feed the fish and essential maintenance (do as much as you need to do in the minimum number of disturbances to the fish); keep tanks (partially) shaded, and make sure all the usual precautions are working i.e. plenty of air and continuous water flow. Minimise temperature and pH change, so ensure all top-up or replacement water is matched before addition to the system. Practice immaculate hygiene i.e. wash your hands before handling fish feed and wash all instruments/tools/nets/etc with dilute bleach solution before placing them into the tanks. Always dispose of salted/contaminated water thoughtfully i.e. not just dumped into storm water drains. If you have non-biofilters in your system, these can be separated and sterilised individually, but it may be better to leave them inline and allow the brine to pass through to kill any nasties lurking there. HTH and good luck. |
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