Recovery advice needed post "toxic" H2O change

[ranmasan]

I was going on vacation from Sat-Wed so I asked my brother-in-law (he keeps angels & gourami) to please feed my fish while I'm gone. On Tuesday night, he decided to do me a favor by doing my weekly water change for me (I do 20% weekly). Since he doesn't know how I do my changes or what to do for a planted tank, used "a little bit of everything" on my shelves.

He did a 25gal change using 7.5mls of Kent Marine Iron & Manganese supplement(I use 8 drops weekly), 35mls of Flourish Excel Organic Carbon (I do 1ml weekly), 5 Tbsp of Aquarium Salt (I only have this in case of emergencies & don't use it in my weekly changes) and worst of all he changed my pH from 6.8 to 6.4 by miscalculating the mix of Seachem's Neutral & Discus buffers (I use an equal ratio to keep a steady 6.8 pH as our local municipal water varies a lot).

When I came home Wednesday morning, all my cats were out & bottom sitting: my S.decorus is *never* out in the daytime & I hardly ever see my S. brichardi, plus two of my pl*cos were just sitting on the sand. I immediately opened the tank lid to see at least 25-30 dead guppies (mostly gravid females). After scooping out the dead guppies, I called to find out what he did & immediately did a 50% H2O change followed by another 20% change later in the evening after scooping out more dead guppies. I've been doing 20% changes daily since to try to slowly bring the pH back to 6.8 and only found 2 dead guppies this morning. 4 of my C.venezuelanus are swimming normally, but have spasmic twitches lasting about 2-3 seconds about once or twice every 5 mins. My only C. trilineatus female sort of "rolls" a bit to the right before correcting herself and sitting straight again on her favorite plant. I lost the youngest C. sterbai yesterday & am hoping to keep everyone else alive. The bigger cats seem to be coping better, but I'm worried I'm not doing enough to help everyone. What else can I do?

I didn't test the inital water on Wednesday morning, but here are today's values:
pH= 6.8
KH= 4.5-5
GH= 7
Ammonia= 0ppm
Nitrite= 0ppm
Nitrate= 40+ppm
Temp= 76F
Tank size= 75gal long
Substrate= 80/20 sand & gravel
Filtration= Fluval FX5
Furnishings= (not sure really what's important, so listing everything, sorry) Asst driftwood, mopani, granite/quartz, hollow plastic root structure, 12" bubble wand & 4" bubble wand on Whisper AP 300 air pump, 2 PVC pipes & asst ceramic mini caves, Java ferns, Anubias nana & barteri, camboba & *lots* of duckweed
Tankmates= lots of guppies, 1 S. decorus, 1 S. euptera, 1 S. brichardi, 1 P. armatulus, 1 Ancistrus cf. cirrhosus, 1 Baryancistrus sp. L081, 1 Panaque sp. L002
Cories= venezuelanus, trilineatus, sterbai, duplicareus & similis
Tank has been running in current location for almost 4yrs & for 3yrs at previous location

[Coriequest]

I was told you can also do smaller changes more times a day as long as the water is neutral. This makes me so sad. What about adding a biological support like Nite Out to get your bacteria back in balance and air stone? You could add an extra filter and carbon, make sure you change it in three days as it loses it effectiveness. No lights, or possibly move them to a tank with perfect water drip acclimating them? In any case, good luck.

[Jools]

I note from your "My Aquaria" records a picture of the tank that it has an airstone. That's good. I'd maybe add air driven carbon filtration to the tank but nothing else. I would feel unsure of what additives might do to an unknown starting point.

A shift of pH from 6.8 to 6.4 wouldn't normally wipe out Guppies in my experience. I worry the other additives might be more problematic. I'd suggest it hard to work out what did the damage in such a cocktail.

With the mix of fish you've got, you're probably better keeping them where they are than farming them out to hospital tanks. Maybe shift the Synos? But, other than the carbon, I'd just go for 10% water changes daily and no food for a week to two weeks.

Jools

[ranmasan]

Thank you, Coriequest & Jools -- I'm leaving shortly to buy some carbon filters now. I've got some extra air pumps & stones (4) & will move out the bigger cats after a nice slow acclimation to the other tanks (water parameters are all good, but they have none of the other additives). Will stop feeding the main tank as recommended, but with the Synos in the other tanks, should I hold off on feeding all the tanks for now?

[Coriequest]

How are they now?

[ranmasan]

As of this evening, I'm down by six assorted cories, a dozen more guppies & one zebra loach. The deaths seemed to have stopped for now, but I've definitely got fin rot on a number of the fish in various stages, the worst case being my youngest C. duplicareus who has completely lost his tail. I've been dosing the whole tank with Melafix + Pimafix & am on day seven of the treatment (I removed the carbon before starting the treatment).

I'm wondering if I should do a large water change & give them a break for a few days before starting the treatment again or should I just keep going until everyone seems to have repaired the fin damage?

[Coriequest]

Hi, I see you are in the Bay area... are you in SFBAAPS? If not you can join and Diana Kostnik can give you far better advice than I can. Or someone else here although in general a lot of the sick fish questions don't get as much response, probably bc people are hesitant to tell something that might not work. I am not a fan of Melafix and Pima fix. Usually lots of clean water with proper parameters and real medication if it is needed. Your poor fish. I am so sorry. But where there is life there is hope.

[ranmasan]

Thanks, Coriequest, as you've suggested I'm going with water changes. I'm only at the very basic level of plant keeping in my tanks, just enough to keep my cats happy .

I've been pouring through all the older posts in the various forums here re: Melafix & have decided to do a 50% water change today, stop the Melafix+Pimafix treatment, continue with the 10% water changes that I've been doing daily as Jools had previously recommended & add some salt to the aged water before adding it to the tank. I start feeding them again on Thursday (they've been "fasting" since 9/2) & I'm certain that they'll be very appreciative of some thawed bloodworms by then. I can't find anything online that is listed as a "catfish safe" fin rot treatment aside from the Melafix & I think medicating with anything else will just stress the tank even more. Fingers crossed that will do the trick!

Once the tank seems to have settled back to normal, I'm definitely going to increase the number of guppies that I've been giving to my LFS (1 large float bag every 2-3 weeks) as they're just so prolific. Wish I had room in the house for a really big tank to keep everyone happy.

[corylady]

boy did u take a hit! i breed corys and do a lot of water changes to mimic rainy season in S,America. i use API stress coat. i do 90% water changes w/unaged tap water w/nostress to the fish. i have also used it on stressed fish w/good results. my girlfriend had a botia laying on the bottom, white slime coat. we used 1/2 dose of stress coat and the fish was fine in 3 days. it doesn't always work depending on the conditions but in some conditions it can't hurt to try. sorry for ur loss.