I have an established 20-gallon tank (since January 2012) with four male platys in it. (Some other residents have been moved out to a newer 50-gallon tank, which is doing fine.) The most recent addition to the 20-gallon was a male platy added several weeks ago. All of the platys LOOK fine. However, over the past few days they have seemed to be a bit less active, with today noticeably so -- especially one male, who is sitting at the bottom of the tank. (The other three have spent much time sitting at the bottom of the tank today, too, but they've been swimming more since I started this post.)
Most water parameters look very good: nitrates and nitrites around 0, hardness around 150, 0 chlorine. However, alkalinity and ph are a bit low. KH is a bit under 40, and pH around 6.2 or a bit higher. Last water change was yesterday. (I just use strips to test the tank, but I see a clear difference between my 20- and 50-gallon tanks.)
I put a handful of small sea shells (rinsed in warm water) into the tank today in hopes of adding a little calcium. I also added a tablespoon of kosher salt (not that a tablespoon will do much in a 20-gallon tank, but I didn't want to overdo it).
Can anyone tell me what's going on? Are my platys in danger? I thought they were hardy enough to tolerate a pretty wide pH. Was I wrong? Is there anything I should do?
One other thing to note: I had a couple of crazy cory cats in with them until today. I wondered whether their crazy swimming was stressing the platys before today -- or whether my transferring the cory cats out today (they were hard to net) also stressed them. One more possible source of stress: The newest male may be the "alpha dog" -- though I've never seen him picking on the others. Nonetheless the two previous assertive males are less so since the alpha dog was added. One of them is the one sitting on the bottom of the tank. (The fourth male -- I think it's a male -- is a fry that's about two or three months old. Fairly big, but probably still immature enough not to worry anyone.)
Thanks for any help.
TJ
Most water parameters look very good: nitrates and nitrites around 0, hardness around 150, 0 chlorine. However, alkalinity and ph are a bit low. KH is a bit under 40, and pH around 6.2 or a bit higher. Last water change was yesterday. (I just use strips to test the tank, but I see a clear difference between my 20- and 50-gallon tanks.)
I put a handful of small sea shells (rinsed in warm water) into the tank today in hopes of adding a little calcium. I also added a tablespoon of kosher salt (not that a tablespoon will do much in a 20-gallon tank, but I didn't want to overdo it).
Can anyone tell me what's going on? Are my platys in danger? I thought they were hardy enough to tolerate a pretty wide pH. Was I wrong? Is there anything I should do?
One other thing to note: I had a couple of crazy cory cats in with them until today. I wondered whether their crazy swimming was stressing the platys before today -- or whether my transferring the cory cats out today (they were hard to net) also stressed them. One more possible source of stress: The newest male may be the "alpha dog" -- though I've never seen him picking on the others. Nonetheless the two previous assertive males are less so since the alpha dog was added. One of them is the one sitting on the bottom of the tank. (The fourth male -- I think it's a male -- is a fry that's about two or three months old. Fairly big, but probably still immature enough not to worry anyone.)
Thanks for any help.
TJ
