Golden Algae Eater Getting Black Goop on his Belly

[PURP]

Hi all
I have searching for a while online trying find help with this, to no avail. I would be most grateful if someone here could help me.

I have a gcae named Lemmy. He (she?) is 4 years old. He is in a 75g tank that uses an external pump rated for up to 300g. I do weekly 25% changes, and the water is always crystal clear (I can read a newspaper through it lengthwise). The chemistry numbers are always perfect - Ammonia/Nitrate/Nitrite all 0, with a pH of 7.0 and hardness in the ideal range.

He has a wide variety of tank mates, most of which are smaller than he. There are four that are about the same size - red-tailed black shark, flying fox, and 2 rose-lined sharks; the red-tailed black shark sometimes bugs Lemmy, but nothing aggressive... And the other three are frightened by the algae wafers floating by. The only bigger fish, is Plato, a 14-15" pleco, who pays no attention to anyone. Lemmy and Plato have been tank-mates since they were both smaller than my pinky. There is no signs of aggression from any of them, they all just do their own thing.

A few weeks ago, I noticed that Lemmy had small dark (almost black) patches of what looked like a tarry residue on his belly. It has since spread, in patches around his belly and up his sides. No other fish in the tank seems to be affected. I did a two-week regimen of Melafix and Pimafix, but his illness continues to progress. Today I noticed that he has a small gash on his right side (See pic). Can somebody please tell me what is going on with him and what I can do to help?
Thank you

 

[FreshyFresh]

Purp, welcome and that's a nice looking tank!! You're doing well in that you do indeed change some water weekly and you measure your water parameters, but zero PPM nitrate isn't possible in a tank of this size, with this stocking level unless you're doing a large water change many times per week. Not sure what you're using to measure water parameters, but most of us use the liquid dropper kits like the API master test kit. The nitrate test can be a bit tricky and is often done wrong, leading to false readings. Hopefully your fish's issues are not high nitrate exposure related, but that's my guess at the moment. I'd eventually do much larger weekly water changes, like take the water right down to where the fish can barely swim, add your dechlor per full volume of tank (Seachem Prime or Safe being excellent ones), then refill.

Issue is, I guarantee your nitrate creep over the course of a week given the stock you have, exceeds the 25% you are reducing it by with just a 25% weekly water change. I'd start by getting a true reading, then do a 25% WC every day for a week or two. Measure your nitrates and monitor your fish's health, then conclude with LARGE weekly water changes. Ideally we don't allow nitrates to exceed 20ppm on day 7. 20-40 is generally OK. More than 40ppm is like smoking a pack a day for the poor buggers.

 

[PURP]

Thank you FreshyFresh for your quick reply. I have been meaning to pick up one of those API master test kits (the one in the blue case... Xmas is coming, I guess). I have been using test strips for monthly checkups because I've never had any unhappy or sick fish, except for the occasional 3 year old molly passing... Stuff like that. I know that I am guilty of overstocking… There are quite a few more other than the ones I listed above (see pic).

This page keeps deleting my posts so I'm going to have to do this in pieces. >:0

 

[PURP]

I've been trying to gradually introduce real plants, but Plato (the Plec) keeps ripping them out... I've read that they help stabilize the water chemistry. As far as the severe water change regimen that you're suggesting, is that safe for the bacteria (the good kind)? I've always been cautious about removing too much water at once… Usually no more than 35%. I have been toying with the idea of setting up a constant water change system similar to an air exchanger in your house... So that fresh water is constantly trickling in. Do you know of any reason why that would be a bad idea?

 

[PURP]

Thank you FreshyFresh for your quick reply. I have been meaning to pick up one of those API master test kits (the one in the blue case... Xmas is coming, I guess). I have been using test strips for monthly checkups because I've never had any unhappy or sick fish, except for the occasional 3 year old molly passing... Stuff like that. I know that I am guilty of overstocking… There are quite a few more other than the ones I listed above (see pic).

 

[PURP]

I should mention that I am using water from my own well. It doesn't require declorination, but I add a dash of ATM Paradigm to every bucket that I put in. I have ATM Colony and Seachem Prime as my base, I only add a few drops of the Prime during larger water changes. I only purchased the Prime because I wasn't able to get more ATM Outbreak anywhere locally. Realistically, I guess I could just use straight water and let the bacteria look after everything else. I have small tanks (for babies not wanting to get eaten) on my kitchen counter next to the sink and I always top them up with the sprayer part of the faucet... Gently, of course.

 

[FreshyFresh]

The only time changing 'too much' water at once can be an issue is if your fish have acclimated themselves to the conditions that are associated with a very high nitrate environment (a bad thing). Your bio load requires more than 25-35% water change per week. I would do daily 20-25% WCs on your tank for a week or two and monitor your fish. Once you've established your nitrates don't exceed 20-40ppm, do a weekly ~80% WC. You could never change too much water on a healthy tank. On some of my tanks, I dump the water right down to where the fish start flopping over onto their sides.

The beneficial bacteria that you are referring to live on all the hardscape in the tank and on the bio portions of your filtration that you should swish/squeeze out in tank water when it becomes plugged. Most of it will be in your bio media, which is the magical "gold" for any tank. This bacteria does not live in the water column. Just as an example, I never do less than a 50% per week WC on any of my tanks. That's a standard amount, far from extreme. Some fish like discus require big water changes every few days. Trust me! I didn't know any of this when I started in the hobby 35yrs ago! I thought it was normal for fish only lived a few months or so. LOL.

 

[PURP]

Thanks again.

P.S. My posts keep disappearing... Is that common here?

 

[FreshyFresh]

That's a nice looking tank! I hear you in that large water changes can be an issue when you're on well water. I know many (even the DEEP ones) in my area were running dry this past summer. Luckily I'm on city water, but are on an old septic system. For this reason I pump my tank waste water out into the yard/garden.

 

[PURP]

Hi again
Just wanted to let you know that Lemmy has just about recovered entirely. The black spots are about 90% gone and he's flying about like he used to a long time ago. It's been a long time since I've seen him this happy. I bought the Nutrafin test kit (the one in the blue suitcase thing), so no more relying on strips. What's troubling though is that I tested the water straight out of our taps and nitrates were at 40ppm. I guess it's time to bleach the well...

Lemmy and I are both grateful for your help and wish you a merry xmas.

 

[PURP]

Oh, and thank you for your compliment on the tank. That was my Christmas present last year. I still don't have it exactly the way I want it… I'm trying to get more plants in there but my plec keeps destroying them. That's Lemmy stuck to the glass vertically on the bottom to the left and my Plec on the right. I've been trying to get rid of all the artificial decor, but it's been a slow process. :0

 

[FreshyFresh]

Yikes. 40ppm right out of the tap is a bit alarming. 40ppm in the fish tank isn't the end of the world as long as you don't let your nitrate creep up too high over the course of a week. If you change 50% of your water, you drop your nitrates by 50%, so if you're starting with 120ppm, one 50% WC only takes you down to 60ppm.