Cory Losses

[wkndracer]

Puzzled by issues this year involving illness and loss on new fish.
Following Coryman's post from '03. Posting his Q&A first for the start adding detailed time line following it.

ID/pictures of the fish concerned.
No consistent symptom of external change other than color loss as the fish goes very pale (near white) and dies. 3 exhibited fin rot, 2 minor fuzz (fungus?)
1. Water parameters
a) Temperature range. 75-78°F changed gradually with treatments.
b) pH. 6.6-6.8
c) GH. 3-5
d) KH 2-3
e)Ammonia, Nitrite, 0ppm tested regularly/almost daily.
Nitrate, 20ppm (dosed for plants)decreasing due plant uptake and WC.
f) Water change frequency; as needed 4 times during a 30 day period twice being 50% or greater.

2. Tank set up
a) Size. 20gL
b) Substrate. Flourite and sand.
c) Filtration. HOB 280 w/bio wheel
d) Furnishings. water sprite, chain swords, crypts, sunset hygro, java moss, java fern, 5 pieces of petrified wood (long term use non issue)
e) Other tank mates. 25 Otto's, small group of common snails.
f) How long has it been set-up? Burned(H2O2 20ml/g 24hrs.)/Dumped and reloaded 10/2/10. Cycle stabilized (filter material seed from a display tank) and reloaded with fish 10/26/10

3. Symptoms / Problem description
Fish losses at 1-2 per day after 13 days in house.
4. Action taken (if any) 5. Medications used (if any); Combined answer.
Aquarium salt (1/2 dose) 1tbs/10g Added slowly over two days, 57grams total. Held water w/o change for 5 days then 50% WC
Maracyn II 1/2 dose(gram neg), Metronidazole(gram pos) 250mg/10g combined treatment.
flubendazole 10% 1mg/4 day standing treatment of a single dose.

Time line of events;
LFS purchased 10/26/10 were 25 Corydoras leucomelas – Blackfin Corydoras (panda) and 25 Otocinclus affinis (Otto's).
(I know, I know, LFS agh!!!!!!!! (the kiss of death))
Because I'm setting up two more 55g tanks and Otto's are so darn touchy with changing water parameters (in my experience). Shipping them (ordering online) is something I've never done. Anyway I made arrangements for pick up on delivery day in the shipping bags. I was at the store within 15 minutes of the arrival.
The water in the bags had a faint green tint and stunk like the Indian River in Titusville, Fla. . Fish look fine, Problem with tested TDS of the bag water.
The water in the shipping bags tested 743ppm on the TDS pen,
concerned about the shipping water (25 fish in one big bag of green water)and a huge parameter change I made at least one mistake, Knowing as soon as I opened the bag (add oxygen to shipping water) the ph spikes and ammonia can burn the fish. I dumped most of the water, added a drip line and added tank water 1 cup at a time until the TDS dropped to within 3x of my tank. Then added the fish to the quarantine tank and no losses for 13 days.
THEN THINGS GO WRONG!
(Really frustrated actually)Should have had Prime on hand.

This is my second/third round of problems trying add more Cory's and I'm without a solid clue overall???????????

11/8 2 Dead panda's when Sherry (my wife) got home. First loss @ 13 days into quarantine. Temp 75F. Tried shrimp pellets and cichlid flake for the hunger strike the last week. I have been feeding a couple of algae wafers nightly. The Cory's in my other tanks love them. The wafers remained untouched while the lights are on in this tank. Dosing Metronidazole day 1, 500mg.
TDS 314ppm, 6.9pH, NO3 20ppm (dosed), PO4 2ppm, 5dGH, 2.5dKH, NO2 0ppm, NH3/NH4 0ppm.
Symptoms; Nothing but hunger strike.
11/9 Pull another dead Cory before leaving to go to work.
Metronidazole day 2, 500mg.
11/10 Rinse filter pad and change 3g with RO. Dosing metro day 3, 500mg.
11/11 Single Cory loss. Symptoms; tail rot and bloody base to the fins. Tail rotted off to a stub!! Threw him into the freezer. Switch meds to marcycn II @ 1/2 dose for Cory's day 1. (based off info from Planet Catfish)
11/12 30grams (1 tbsp) sea salt, 1 pack marycn II (gram neg) & 2 tabs metro 550mg day 3 (gram pos) added. Observed one larger panda with a small spot next to its eye yesterday that’s a large fuzz ball today.

11/14/10 Working 26hrs total in 2 shifts in 2 days missed yesterdays med dose. Find 'fuzzy eye' dead this AM but no fuzz on corpse and his eye is protruding out in death. Salt took until this morning to complete the addition of 1tbs dissolved in a cup then added without stirring. Maracyn II (1/2dose), Metro 500mg continues day 4. Rinsed filter floss. Add another 27g of salt, with this addition salt dosing will be 50% of the recommended fresh water level. Cory's don't like salt according to web info.
Symptoms;Possible ICK, fin rot, fungus???, Ammonia burn?????
6.8pH, NO3 10ppm, PO4 2ppm, 5dGH, 2.5dKH, NO2 0ppm, NH3/NH4 0ppm.

11/15/10 Add flubendazole 10% to the soup 1mg mixed. Dustin (my son) pulled all the snails he could find using tank tweezers because the meds will kill the snails adding to the crap in the tank.
11/16 Another gone with a rotted tail. Maracyn II (1/2dose), Metro 500mg day 5.
11/17 Another gone with no outward signs Maracyn II (1/2dose), Metro 500mg day 6
11/19/10 Today 2 more found dead after work. Very slight damage visible on one behind the gills almost appears to be a tiny blood blister.
Maracyn II (1/2dose), Metro 500mg day 6.
6.8pH, NO3 10ppm, PO4 3ppm, 5dGH, 2dKH, NO2 0ppm, NH3/NH4 0ppm.
11/20/10 Large water change and add activated carbon. Which I thought the Otto's would react badly to so I can remove the flubendazole treatment.
All medication's stopped at this point.
TDS 572ppm, 6.8pH, NO3 10ppm, PO4 1.5ppm, 4dGH, 3dKH, NO2 0ppm, NH3/NH4 0ppm.

Not a single Otto loss I can identify (they swim too fast) but the Cory's keep dropping and currently this morning only 6 remain.

While not listed in the daily tracking Nitrite and Ammonia levels have been tested daily. Also the tank has no odor.

Can ammonia burn caused losses be this delayed and spread out? Minimum secondary indication displayed yet consistent loss day after day? Speculate that the supplier may have done a better pre ship purge on the otto's but its only a guess.
Anyone taking the time to read all this THANK YOU VERY MUCH!!!
Any further suggestion on a future course of action?
I have panda, paleatus, albino and julii corries in my other tanks using the same RO water and treatment (GH,KH additives)without health issues long term >2yrs. so I don't think it's water related.

[MatsP]

Your TDS is very high (probably due to the aquarium salt). I don't know if this is part of the problem, but I doubt it's a great help at present.

It is highly likely that the TDS of the shipping bag is high due to high levels of ammonia [a very good conductor ion!]

I'm not sure what to suggest other than try to get rid of the concoction of medications and salt in the tank by way of water changes, and check for nitrite and ammonia spikes.

--
Mats

[wkndracer]

Thanks very much for the reply. Carbon and the large WC should have removed the medications. I debated adding an external UV unit but didn't see the point after whats happened to date. TDS went from the original 282 to 756ppm after the salt addition then dropped after the WC. I'll do another WC to drop the remaining sodium content that should completely reset the TDS <300ppm level.
I do keep one hard water tank 8-10dGH, 4-5dKH with regular TDS readings ranging 368-544ppm so the TDS wasn't a red flag knowing the aquarium salt caused it but I'll get it dropped further right now, thanks again.

Any experiences with ammonia burn or resulting issues from it? This is my first experience with a large number of fish received in a single bag.

[MatsP]

Sorry, can't really help there. Good clean water certainly helps.

--
Mats

[wkndracer]

Got it done. 80%WC.
Changed out the 5 day old carbon with another 80grams.
Temperature remained 78°F, TDS down to 316ppm,
7.4pH(when the O2 stabilizes this will drop a bit),
4.5dGH(Seachem Equilibrium 14g),
2.5dKH, NO3 5ppm, PO4 1ppm, NO2,NH3/NH4 0ppm.
There's no mum, leaf litter or left over food in the tank. Not that there was any to remove prior to the WC. Clean as I can get it. One looking pale and five normal in color without any other defect present. The herd of Otto's and the remaining Cory all scattered and displayed normal excitement during the disturbance of the WC. Thanks.

[Bwhiskered]

The best medications that I have found for corys or most other fish and their problems is Jungle Binox. I have even successfully treated young cory fry that have clamped up fins. The only problem is that it kills plants and should not be used in a planted tank.

[wkndracer]

Thank you for the recommendation but they're done. Only three remain today. Pale as a ghost and then becoming one. The last two lost did have a protruding eye, (bulging) but no other symptom. Another is pale today.

I now have to decide what to do with the 25 Otocinclus affinis (Otto's).
They have been unaffected throughout the whole ordeal with the cory's.

Water tests perfect.