I need to stop creating new threads, but this is a different main subject...
1. How do you ensure there are no diseases in a tank/fish?
I am watching after my friend's guppies and plecos at this time (some of you may have seen my rant) and I transferred all her fish to an empty 15gal I had laying around. I'm using her filter and heater (suitable to the size of the tank) as well as her decor, but I put my gravel in (some I had laying around). Two things I want to do a) maybe take a couple of her guppies and add to my other tank b) use the tank they are in when/if she takes the other fish back. There are no visible signs of diseases, and there have been no mysterious deaths (other than the bala shark that was in there, but I never saw him eat, I think that was it), and everyone seems active and healthy. I just don't want to put fish into my other tank that may have diseases.
2. My fish are less active.
I have a 20 gal with 5 black skirt tetras, 2 neon tetras and 2 otos (all under an inch) that has been set up since around September. They don't seem unhealthy. They are eating (although they do not speed to the top of the tank when they're fed like they used to and go nuts over it...they wait till it falls lower), there have been no deaths (except I lost one of each kind of tetra as they were added about a day after they were added but that was months ago) but they spend most of their time hiding. I recently added a significant amount of fake plants to the tank and wonder if they just hide more because there are more places to hide? They seem to have changed their behavior since I added these plants.