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Rapidly Dying Fish

3K views 4 replies 4 participants last post by  Lupin 
#1 ·
I've been running a 30gal tank for about 9 months (new to the hobby) without any issues short of build-up of algae/cyano requiring cleaning. After treating for algae (Tetra Algae Control -- 3 doses over 9 days), on 3/22 (post the last treatment), I added two new algae eaters to my tank -- one L091 red-fin pleco and one clown pleco bringing my tank total to 12 -- 2 angels, 6 dwarf neon rainbows, 3 clown plecos, and the L091 red-fin. 4 days later, two of the rainbows were dead on the bottom of the tank. My water levels tested at: ammonia=0mg/L, nitrite<0.3mg/L, nitrate=25mg/L, Phosphate=1-2mg/L, pH=~7, temp ~80degF.

While doing the tests on the water, one other rainbow acquired a yellow/orangeish color cast (VERY noticable), turned upside down, and fell to the bottom of the tank -- gills twitching. Moments later, another rainbow started having breathing difficulty. I performed a 60% emergency water change (treated with 2x the usual new water dose of Seachem Prime Conditioner). The two fish perked up, but died hours later in the same manner. When a fifth neon started exhibiting the yellow/orange color change and breathing difficulty, I did another 50% emergency change. I took the fish exhibiting symptoms to the local fish store and they noted raised scales and white lips on the rainbow but did not have an idea what would cause these particular symptoms and such rapid death. Within 24 hours, all 6 rainbows had died (the first 4 within 6 hours of each other).

The LFS suggested treating the tank with an alternating combination of naladixic acid/K-mycin and an anti-parasitic (formalin/malachite green). After acquiring the anti-biotics and before even starting them, the L091 was on the bottom of the tank with breathing difficulty (5 days post-purchase). Water levels now test at: ammonia=0mg/L, nitrite<0.3mg/L, nitrate=12.5mg/L, phosphate=0.25mg/L, pH=a touch under 7.0, O2=~8mg/L, GH=3dH, KH=2-3dH, temp=~75-76degF. I treated the tank as suggested yesterday with naladixic and formalin/malachite. This morning my L091 was upside down on the bottom of the tank dead.

Any ideas as to what would cause this? I'm suspicious of the two new fish, but the LFS tells me there's no way that anything they carried would sweep the tank in 4 days killing that many fish. At the rate that my fish are dropping, I'm afraid I'm going to lose them all... Thoughts?
 
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#2 ·
ok, doing a 50% and 60% water change could have made the problem worse. the max amount of water ever to be taken out at any given time is 15%, . also, the water source could have been the problem. raised scales is a obvious sign of dropsy. exsessive nitrates or bad feeding habits coused this. did the fish act strange before this happined? also. the plec probably found your water levels unsuitable. white mouth is a sign of fungus, poor water quality.
 
#3 ·
There was no swelling in any of the fish and the "white lips" the fish store described were -- as they put it -- dry as if lipstick had been painted on the fish lips. It was not the white cottony look of fungus and they clearly didn't think it was. The woman there said that it's most likely some kind of bacteria but they were unsure.

The only odd behavior I noticed from the fish prior to this was a lack of interest in feeding the day before I found the two rainbows dead on the bottom of the tank.

What I don't understand about this is the fact that the tank had been running for 9 months with the same source water for changes (~25-33%).... around the same levels (nitrates running between 12.5mg/L and 25mg/L)... and all of a sudden, 4 fish die within 6 hours, 6 within 24...?

If this was a water quality issue -- wouldn't I have seen something less dramatic or over a more prolonged period?
 
#4 ·
ok, doing a 50% and 60% water change could have made the problem worse. the max amount of water ever to be taken out at any given time is 15%,
what makes you say that? doing larger partial water changes can help bring amonia down and keep the tank clean. i would say 30% every week is good, but up to 50% is fine., and especially if you have been medicating and need to put a new medication in.
 
#5 ·
wmessmer said:
There was no swelling in any of the fish and the "white lips" the fish store described were -- as they put it -- dry as if lipstick had been painted on the fish lips. It was not the white cottony look of fungus and they clearly didn't think it was. The woman there said that it's most likely some kind of bacteria but they were unsure.
Is it only the rainbows that are affected? I was afraid of this because the white lips gave me a signal in the air that this might be false columnaris. I had the same situation before and have a nasty feeling this one will answer your situation terribly.
Mycobacteriosis is a systemic, chronic, progressive bacterial disease, which presents varying clinical signs depending on species and aquarium conditions. The resulting disease may be characterized by emaciation, inflammation of the skin, exophthalmia (Pop-eye), ascites (Dropsy), open lesions, and ulceration. Fish may become sluggish and bloated and develop fin and tail rot as well as scale loss. Skin discolouration on one side of head or body can also be an indication of a mycobacterial infection. Internally, grey-white granulomas (nodules) develop in the liver, kidney, spleen, heart, and muscles. When the nodules develop in the organs, oedema (fluid) and peritonitis may ensue. If infection spreads to the skeletal system, deformities such as a bent spine may be noticed. Eventually, all infected fish will die

There is no known treatment to stop it.
This was retrieved in another site. The moment I read your post, I had known too well your situation may be the same as mine. Suspected columnaris, yet it did not appear to be columnaris judging by how you mentioned the raised scales and white lips which happened to mine before.
 
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