Trouble Identifying Condition

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RVarner

Feeder Fish
Sep 25, 2025
2
0
1
45
SoCal
Have you tested your water?
Yes
If yes, what is your ammonia?
0
If yes, what is your nitrite?
0
If yes, what is your nitrate?
0
If I did not test my water...
  1. ...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.
Do you do water changes?
Yes
What percentage of water do you change?
21-30%
How frequently do you change your water?
Every two weeks
If I do not change my water...
  1. ...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.
Hello! First time poster, new entrant into aquascaping building my third tank (60 Long).

I have a 20 Long I'm using as a breeder. Speckled Yellow Guppies and Rosy Barbs are both breeding a lot. I have new groups of fry about every 3 weeks from both species.

Lately one of the yellow guppies skin has taken on a bit of a aged look and its behavior has become unusually aggressive towards other fish. Especially a particular orange guppy in the tank. I haven't found a good matching condition online and I'm not sure it's just old age but his tank mates aren't displaying this condition or behavior.

The water had reached an acidic state and I've been buffering it with occasional Baking Soda to bring it back to a normal range. Other parameters have been great with the exception of hardness being high.

Gravel substrate tank (Before I learned better), heavily planted with Anacharis. Water is hard due to some local stones in the tank that may be leaching minerals. These fish have been happy occupants for 1 year and 3 months and all their offspring have been healthy.

I removed him from the tank temporarily to give some of the stressed fish a break. But i'm not sure what's causing the skin to look so textured and I don't really believe it's "old age"

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Honestly, that fish looks okay in those pics. First step in identifying the "condition" is to identify the fish; it's a Mollie, not a Guppy. It wants harder, high-pH water and generally wont do well in acidic conditions long term. Breeding Mollies and Barbs together isn't ideal as they want differing conditions. One or the other...or both...will suffer in a compromise situation. Hard but acidic water is a relatively uncommon combination in nature, not ideal for either species.

Is your nitrate level truly zero? Can't see how that's possible, in a small tank with only a 30% water change every couple weeks. Your plants will help, but the amount of nitrate they can uptake would be limited to that produced by only a very few very small fish. We don't know how crowded your tank is so can't really say, but...zero nitrates sounds suspect.

I think the first simple step to take is not to grab a box of white powder; it's grabbing a bucket or hose and changing much, much more water...much, much more often.
 
Thank you! I'm not sure why his texture/behavior has changed, but there may be a social element to it after observing them some more. The moment I removed the aggressive molly, one of the guppies was immediately tailing and glued to one of the yellow mollies. There appears to be a particular issue between these two specific fish.

It didn't feel right calling them guppies although that's what they were labeled as at PetCo. These are the first fish we bought for my daughter after she brought a crawfish home from a school project. I didn't even know what tank cycling was back then. I started getting into aquascaping and now it's my hobby and she's not interested. ha!

The 20 Gal Long has:

4 mollies, 2 guppies, 3 rosy barbs, tiger pleco, mystery snails, ramshorn snails, 5 amano shrimp.

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I've been moving the fry/juveniles to the 60 gal long tank. This tank will be reset eventually so I don't put effort into making it look fancy.

Dipstik brand typical ranges:
ph: 7.0
alk: 50
carbonate: 50
hardness: ~250
nitrate: 0-10
nitrite: 0 to <1
Chlorine: 0

This test was ~30min after feeding this morning. So the nitrate is reading higher than normal here. It's usually 0 - 10.
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The anacharis had a trimming in this pic where I pulled out ~35% of it, so the plant mass is pretty high, I trim, re-bunch and re-plant. The tank does seem to want to go acidic and probably 2x a month right now I'll either add Ph UP or 1/2 teaspoon of baking soda to bring it back into range. I don't know why yet but it happens slowly and there aren't big swings happening when I test multiple times a day (usually only test that frequently if I feel liek I'm observing behavioral changes in the fish).

Topoffs are weekly with water changes bi-weekly (Sometimes I do 50% when I gravel vac but 30% is a more accurate average). Gravel vac is ~1-2 a month. Maybe 2 month gap on vac if I'm lazy.

The 60 gal has:

~17 rosy barbs, ~45 mollies (fry to juvenile), 17 amano shrimp, 2 long fin plecos, nerite snails.

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This is my first tank being done more correctly, but I'm still a beginner. I'm using it for the fry's and what I will eventually sell to a local shop, although I'm not sure if I'm going to get into breeding in a serious way yet.
 
Going off of your test strip:

1) Nitrite should read 0. Anything greater than zero should be treated like a bump in your cycle (or an immature one). Be ready to water change, especially 1.0ppm or over.

2) As mentioned, Livebearers thrive in mineral rich water. You may want to add some crushed coral to your filter/ substrate. It'll bump up your KH (and in turn, PH) and also add a bit to the GH numbers. Livebearers won't complain.... they'll enjoy. Crushed coral can help to stabilize the parameters closer to what they prefer.
 
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