New tank blues--dying fish

[flowman]

Hello all, I'm losing fish and looking for suggestions. Sorry for the length, trying to provide complete background:
55g (208l) tank, 48" long, etc set up mid August with gravel substrate (previously used), hang on back filter and large sponge filter, combination of artificial and live plants (Val, Am Sword, Java fern, C wendtii and A nana petite). Fluval Aquasky light. Planning for community (tetra) tank, perhaps eventually with a pair of Kribs or Apistos as feature fish. Hardscaped with two large pieces of mopani wood ordered from thatfishplace.com--didn't treat the wood before adding it, but it's been in the tank for over 3 weeks, covered in spots with pale white fuzz. After reading more re: corys I added an area of fine aquarium sand 1" deep that's about 1/5th the bottom area--the rest of the gravel is rounded pebbles about 5mm in diameter.

Cycled using the sticky link here (fishless method with liquid ammonia), tested every other day, saw nitrite start to rise after about 2wks, added half dose of ammonia, NH4 back to zero in 2 days, nitrite continued to rise (peaked at over 5ppm), nitrate up to 20ppm. On Sep 30 nitrate was at 20ppm, NH4 and NO3 at zero. Thinking it was cycled (I still do, see below) I did a 10 % water change and added 8 small glolight tetras, 1 tiny SAE, 5 julii corys and 6 cardinal tetras. Temp in tank 78F (25.5C). Floated bags for about 45 mins, gradually added 2c tank water to each bag, then poured fish from each bag into net (ie disposed of LFS water) and gently added fish to the tank. All of them dispersed, explored, seemed fine. Fed a few hours later, ate eagerly.

The next morning I noticed one cardinal had a white patch at the base of the dorsal fin, about the same size as the fin. Researching possible treatments, fish died a few hours later. Found one cory dead that night. Tested for ammonia, 0ppm. Did 10% water change anyway, vacuuming gravel.

This morning I found 2 more corys and 2 cardinals dead, and I can't find one cardinal. Glolights, surviving corys and SAE seem fine. Did a complete water test:
temp 78
ph 6.8-7.0
NH4 0ppm
NO3 0ppm
NO4 10-20ppm
Kh 89 ppm
Gh 125 ppm (previously around 90)
Phos 0ppm

Did a 20% water change (neutralizing with Stress Coat+ as before, matched to tank temperature). I noticed that the white fuzz on the mopani wood seems more pronounced, and fish occasionally seemed to graze on it, so I took out the large piece, scrubbed it, and I'm currently boiling it. I haven't done that with the other piece (which also has some fuzz) because I'd superglued the java fern to it.

I'm baffled and open to suggestions--the fish were purchased from a LFS that has a good reputation. Thanks.

 

[fishyfun&fans]

Sorry I’m really not sure myself wish I could help!

although I am sure someone will have an idea keep checking up

 

[Byron]

This is one possible issue, that being the "white fuzz" on the wood, which is fungus. Some fungi are harmless and fish like grazers will eat it. But there are toxic species of fungus and these can kill fish. I had this several years ago. Unless you can get a trained microbiologist to examine the fungus, there is no way to tell what species it is.

How are the fish behaving? I've no idea as to your level of experience, so thinking they are acting "fine" may be misleading. In my case, the fish had been in the tank for several years when I added this piece of blondish wood, and within a day the water got slightly cloudy and the fish, especially the cories, just sat respirating much more rapidly than normal. I saw the fungus and that was my first reaction. This is a possibility here. Removing the wood from the tank would tell you. I would take it out, do a major water change (75-80% provided parameters of tank and tap water are relatively the same--this means GH, pH and temperature), use only a conditioner. If the fish seem more active and none die, the wood fungus was the answer. This is safer than dumping in treatments that will cause additional stress and be pointless if they are not effective for the problem. Do a good vacuum into the substrate in open areas during the W/C, and rinsing the filter media is advisable.

It could be internal protozoan. Fish just begin dying with no external symptoms.

Bad genetics I would discount as this is across several species and rapid, which is not likely going to be genetics.

 

[Bruce Leyland-Jones]

I'd concur with @Byron as fungus and fungus toxicity as being prime suspect.

 

[flowman]

Thanks all, good points. I'm wondering about putting in the piece of wood that I boiled for an hour...wonder if that might have killed off any fungus. I wish I'd boiled it all after I saw how much color and scum came off the wood. Lost another cardinal today--I'll be monitoring closely. @Byron, I thought about source water--ph, GH and KH of tap water are all similar to tank conditions (which makes sense, since that's what I started with). Thanks again.

 

[flowman]

Oh, and as for behavior, I've kept fish for years, took a break for the last few...normal respiration and behavior, no clustering at the surface or near the filter output, tetras shoal and parade back and forth, cory's occasionally dash to the surface for a gulp of air--in other words nothing unusual. The first cardinal (the one with the large whitish patch) started drifting down and backwards towards the end, but shoaled with the rest until then.

 

[Byron]

Oh, and as for behavior, I've kept fish for years, took a break for the last few...normal respiration and behavior, no clustering at the surface or near the filter output, tetras shoal and parade back and forth, cory's occasionally dash to the surface for a gulp of air--in other words nothing unusual. The first cardinal (the one with the large whitish patch) started drifting down and backwards towards the end, but shoaled with the rest until then.

One or maybe two fish dying may not be an issue, but when it becomes several and basically daily there is probably something amiss that does need correction. It still might be worth removing the wood and doing the W/C etc, to eliminate that possibility (or not, as the case may be). Normal tinting from wood tannins is perhaps unsightly but not a detriment, in fact the fish should benefit. And I doubt anything can remove the fungus if it is toxic. I took my wood out and scrubbed it, dried it, then had it in a tank of water (no fish) for 3 months; saw nothing, so put it in another fish tank, and after a couple weeks, fish began dying. There was fungus growing on the back side I couldn't see. Wood went out in the garden.

If fish continue to die unrelated to the fungus, it may be an internal protozoan issue. Metronidazole in the food is the most effective for this, fed exclusively for 10 days.

 

[Naughts]

The first cardinal (the one with the large whitish patch)

Do you have a photo?

 

[Colin_T]

Pictures and video of all fish so we can check them for disease?

White patches on the body can be excess mucous caused by something in the water irritating the fish (eg: poor water quality, yours is ok, an external protozoan infection, chemicals or poisons in the water).

Remove the driftwood and hose off. Put it in a bucket of water until things in the tank settle down, then do a huge (80-90%) water change (as suggested by Byron). Monitor fish and if they stop dying, wait a couple of weeks and put one piece of wood back in the tank. If they are ok for a couple of weeks, try the other bit of wood. If they die again, it's the wood or fungus on the wood.

 

[flowman]

Thanks, I didn’t get any pics of the fish pre-mortem, but I took out the wood (after boiling one piece for over an hour) will monitor and add back gradually. No visual symptoms in remaining fish

 

[itiwhetu]

The white fuzzy stuff will be the problem

 

[Obsessed with fish]

Your fish have fish fungus. Quarantine the sick fish immediately so they don't spread it to the other fish then medicate the Quarantine tanks.

 

[Naughts]

Your fish have fish fungus. Quarantine the sick fish immediately so they don't spread it to the other fish then medicate the Quarantine tanks.

There is no evidence for this statement. A toxic fungus growing on the wood is not the same as a fungus infection on a fish.

 

[Slaphppy7]

One other thing to point out, the Stress Coat "conditioner" contains aloe vera, which has not been proven to be beneficial to fish, and may actually be harmful...you'd be better off using Seachem Prime, or API Tap Water Conditioner.

 

[flowman]

Update: took out wood, did a WC, lost the last 2 cardinals (all 6 died), but all of the other species are healthy. Will monitor and add the boiled piece of wood back after some time. Thanks.