Greetings, folks, and thanks in advance for any help you can offer. I am pretty new to this and anxious to learn and do a good job.
This morning, my husband and I noticed that a few of our platys have redness around the gills. This is most noticeable in the yellow fish in the foreground here, but she's not the only one. At the same time, not all of the fish (or even all of the platys) seem affected.
She is eating and breathing as usual, and isn't flashing. No clamped fins. No hiding, or floating, or hanging out on the bottom. Seems pretty regular other than this.
In case this is relevant, she was born in the aquarium.
This is a planted aquarium with some fairly old plants, and I only recently learned that the appropriate protocol for overgrown stem plants is to replant the tops and, if anything, discard the lower parts... so I've been a little concerned that the plants as they are now aren't as great at utilizing fish wastes as I'd like them to be. (On the other hand, they are converting CO2 to O2, according to the drop checker.) No test has ever (in the nine months that I've had this aquarium) shown elevated ammonia, nitrite, or nitrate levels, however, and lately I've been checking around twice a week. This morning's parameters are given at the bottom of this message.
I just did a water change yesterday. When I do that, I use either Tetra AquaSafe Plus, or Seachem Neutral Regulator--a while back, the water was more on the acid side than it is now, and KH was also low--the person at the pet store recommended the Neutral Regulator because of this.
I have an Eheim 2213. A couple of days ago I changed the carbon filter and rinsed the other filter media (in tank water). I tested the aquarium water several times in the 24 hours following, and parameters were fine (the same as those below). But... right now I'm using the Tetra 6-in-1 and the ammonia test strips. The API Master Test Kit is set to arrive tomorrow, and I will retest with that.
The only other recent change is the addition of a piece of Mopani wood (boiled over and over, each time in new water, until the water was not taking on much in the way of visible tannins).
Any ideas on what might be wrong here?
Again, many thanks for any conjectures/advice you might have.
Tank size: 40 gallon breeder
Cycled,yes or no: Yes
Number of fish: 1 gourami, 4 small pebbled corys, 4 very small clown loaches (destined for a larger tank), 2 large platy (females), 3 small (1.5") platys, several platy fry
Acclimation process: Fish in question were born in the aquarium
Physical signs of illness(IE spots,shimmer,ECT): Red gills
How often between fish additions: Infrequent, but added clown loaches one week ago, and a couple corys the week before that. Before then, no one for perhaps six months.
Waterchange schedule: 25%, once a week.
Tank temp: 75 Fahrenheit
P.S. I am aware (now) that corys and loaches have different enough temperature requirements that they shouldn't be in the same tank... at least this is what I'm assuming, given what I've read about both. And I am also aware that corys do not like salt
in the water, while this can be beneficial to other fish. My plan is to set up another tank for the corys--I hope to have all of the pieces of that puzzle together next week.