mystery illness kill my fish!!!! help please

Question
Mystery sick fish what medication to use?

hi im new to the forum and hoping you can help me and my fishy friends
i have a 170 imp gallon (7x2x2ft) freshwater tank set up for 2 years with fluval fx5 external filer, and external ehiem 2178 and the largest internal fluval filter (fluval 5?) both external filters have spray bars on return, all artifical plants and bog wood

i have lost about 12 fish over the last 3 months, maily raindow fish, and a cory, i now have left in my tank...............
25 clown loach 3" - 7" (my babies) 6 3"-4""+ yoyo loach, 2 small cubotia (spelling?) loach,10 medium rainbow fish, 2 large 2 small plecos , 2 pepper corys, 1 blind albino cory, 1 weather loach, 1 horse face loach and 4 pearl danios, 2 tiger barbs, breeding ammano shrimp and a 6" blue lobster (crayfish)

My bosemani raindows have been getting ulcers towards the back lower half of there body, and 2 red tailed rainbows have swollen red gills one of which has red swollen base of pectoral fins,1 of my corys barbels are wearing down (i have small round p gravel) my big pleco has frayed dorsal fin and both large plecs move (sorta fanning motion) their pec fins and the ones behind (sorry cant think of name) when stationary (they didnt used to do this), 1 small choc pleco had swollen belly but that went down, also some minor scale loss on male australian rainbow fish (fighting?) and two female bosemani.

all fish are twitching, and flashing on objects,seamingly irritated, tho all loaches have no visable signs apart from flashing (thank god) all are eating at present. i Have used meth blue, didnt work, used interpet 9 anti bacterial, didnt work. LFS have given me F-M-G by NT labs, used for ponds but advised ok for my tank at 3/4 dose daily unitl symptoms stop, contains formailin an malachite green, (QT for crustations).
Is there another med i can use? im lost for ideas


ammonia 0, nitrite 0 nitrate 20-50, ph 7-7.5, 40%-50% waterchange every week, gravel clean as i do the water changes, temp 28 deg, water very well airated, i have alway added a salt tonic at every water change (at 50% due to loach and corys) havent tested hardness for a few months but my tap water is very soft.

also if i quarenteen the lobster so as not to murder him (doubt il be able to catch the ammano shrimp  gutted ) when i reintroduce him back to the tank will i reintroduce what im try to irradicate? i know snails and crustations can act as a carrier but are not affected. i dont want to re home him but i also dont want to put him back in the tank if brings these symptoms back

please help
i really dont want to lose any more fish

thanks for any help x


Answer
Hi Cloachlover;

It does sound like a parasite. Especially since the water tests are good. Look closely at the skin on all your fish. Does it look like there are any white salt-specks or "gold dust" on them? White specks are "ich" and gold-dust is from velvet. Both are treated with the medicine you are already using. Sometimes fish can get ich parasites in their gills and you can't see them but the fish suffocate and die.

An additional possibility or the deaths and torn fins is that your lobster may be attacking some of the fish at night. They are very predatory and sometimes have to be kept out of tanks with fish in them.

The rainbows may be having a problem from breeding activity. It's hard to say for sure. If they tend to sleep towards the bottom of the tank they may be getting attacked by the lobster. It's also possible they have developed a bacterial infection.

If you are still losing fish and they haven't stopped flashing after a few days I would try a different medication. You might also want to see if there is a veterinarian or a biology lab that could look at a skin scrape under a microscope for you to identify the pathogen affecting them.

I hope they feel better soon...

At Your Service;
Chris Robbins