Apologies in advance for the upcoming ramble. I've given the background and context as I feel the need to defend myself, as I've been naive and now I'm looking to put things right.
So I've gotten to where I am with fishkeeping on luck, more than anything. I was given my nan's tank about three years back when it became too much of a chore for her to keep looking after it. Her tank was 45L, and when I took it on, it contained about 7 each of neon and black neon tetras. I asked about maintenance and was presented with a toothbrush, an algae brush and a bucket and told to give it a scrub once every couple of weeks, to brush the filter sponge with the toothbrush and to change about a quarter of the water at the same time. I was also given a box of Aquarian flakes and told to give them a small pinch each morning.
The tank was over a decade old when I received it and since then, I've just been looking after it in the same way, following what she did, with the only difference being my purchase of a gravel vacuum to make the job a bit easier. The neons were a few years old when I received them but as time has passed, some died and I attributed it to age, as the tank was "healthy", there was no sign of illness and the others all appeared fine, so there was no cause for alarm. I hadn't really looked into fishkeeping because she'd kept fish for over a decade without any problems and her advice appeared to be looking after the tank and fish just fine.
About a month ago, I came downstairs to find a puddle of water and a small leak. The leak wasn't pouring, it was like a pin prick, but it had clearly been going for most of the night, as the tank was just above half-full. I hastily slapped some tape over the leak to try to stem it, threw some towels down and then rushed down to the nearest fish shop to buy a tank. I couldn't find another 45l tank, so I took an Aquael LEDDY 60 54L tank and rushed home. A quick Google told me to take all my old gravel, decorations, filters and as much water into the new tank as the best emergency move. I moved everything into the new tank, topped it up with dechlorinated water and then hoped for the best. Over a few days, numbers thinned out and I lost about half a dozen fish in total, but as I already thought the fish were old, I figured the shock and stress of the move had done for them and wasn't concerned.
So, just over a month ago, with 4 black neons and 2 neon tetras left, I returned to the fish shop to restock. I think the salesman saw me coming, as I wanted a pick 'n' mix of fish that he was only too happy to provide. I came home with about a dozen new fish, new foods and another decoration for the tank. One of the fish I bought was female black/gold molly, and within a fortnight she'd gained quite a bit of weight so I went looking to see if she was pregnant and found this site (among others) and realised that I had been doing quite a bit wrong, because I'd followed my nan's regime (which was working, to a point) and got fleeced by a salesman. I've been naive about this as a hobby, taking on my nan's advice and then listening to the salesman, trusting him in his role as an "expert" and not assuming he's out just to line his wallet.
I've tested my water with the API Master Kit and it seems pretty good, so I think I've been lucky, but as I'm exploring this site I think I need someone that knows their stuff to tell me what's what because there's a lot to take in and I could do with a bit of guidance to say the least. I've been doing 25% water changes every Saturday, feeding a little bit twice daily and having checked my water levels each time I've done a change, I've not seen any real changes other than the nitrates gradually decreasing.
So, I've got a 54L tank, footprint of 60x30 by 30 high. I've got an oversized internal filter (sponge, suitable for up to 90l that came with the tank and a powerhead suitable for up to 180l), the standard LED strip light in the hood of the tank, some decorations and silk plants, with gravel.
My fish:
4x Panda corydoras (genders unknown)
4x Black neon tetras (genders unknown)
2x Neon tetras (genders unknown)
2x Black and gold mollies (one male, one female)
1x Golden ram (female)
1x Hatchetfish (gender unknown)
My water:
PH - 7.2
Ammonia - 0.25ppm (there's a green tinge, but when I checked my tap water it was the same colour too)
Nitrites - 0ppm
Nitrates - between 10 and 20ppm
Hardness - 52.479ppm/2.94dH
I'm a bit concerned about the ammonia, but I think I read another thread suggesting it might just be the test kit (or my eyes!), as if tap water measures the same, then it's alright - can someone confirm this? I'm also running my old filter alongside the new one that came with the tank, is there any problem in this? Can I "over-filter" the water this way?
I'm still feeding Aquarian flakes, but now have some little wafers for the bottom feeders and I feed a small amount of each twice a day. I've also got frozen brine shrimp and frozen bloodworm, but when I've tried putting them in, no-one paid them any attention, so I cleared them out and haven't tried with them again. Do the fish I have not eat these things? I took them on the suggestion of the salesman and now just feel like a mug...
According to the community calculator, I need more of each of the tetras, another female molly and from what I've read here, I could also benefit from another couple of pandas, too. I also see that my tank is too small for the hatchetfish anyway.
So I'm thinking I should return the hatchetfish and the gold ram to get another female molly... and then what? I don't much like the black neons, they're not very interesting fish (in terms of colour or personality) and I would much rather have more neon tetras in their place, but I can't return them to the pet store and I'll just have to wait for nature to take its course. Given the relative age of my neons, and the stress they've had recently, is it even worth adding to their numbers, or will new members struggle to shoal with the oldies?
From what I've read here, I think I'm getting to grips with it, but I'd rather be sure. If I've missed any vital information or need to clarify something then just ask - I'm still learning the terms!