Hi everyone - please bear with me. I'm one of those people who tends to over-research and overthink everything and I'm very confused ...
We were donated a 10 gallon aquarium about 6 weeks ago by neighbors who were moving out-of-state. They had purchased it for their young daughter and thought that my younger kiddos would appreciate having fish since they couldn't take it with them. I was assured that it was low-maintenance and that the fish were easy to take care of, but I'm discovering that the tank was probably not ever well-maintained or correctly set up to begin with, so I need some help.
My friend mentioned that she'd never changed the water - she'd only topped it off periodically when it evaporated out. She also mentioned that it had live plants in it at one point but she got tired of pruning them, so she'd taken them out and just put in plastic ones. It looked clean initially, but when I refilled it after it came to our house (she'd pulled a lot of the water out to make it lighter to carry) it stirred up all the junk in the gravel that had never been cleaned and was very nasty. She told me to let it settle overnight and that it would be fine. I had no clue what kind of fish we were getting, but I *think* after doing some research that we started with 4 large-ish tetras of some kind, 4 cory catfish of some kind, and some kind of pleco. I'm not positive about the identifications, that's just my best guess.
I started reading fish articles and quickly got overwhelmed by the conflicting information. So far this is what I've done, and some of my concerns/fallout from it:
1. Swapped the neon blue gravel in the bottom for neutral colored gravel, because it became rapidly apparent that the fish were stressed. All of the tetras and the catfish would flock around one spindly little plastic plant in the corner of the tank, and if they came out, the pleco would come out of the big ornament in the middle of the tank and charge them. At the same time that I swapped the gravel, I moved the pleco's decoration-cave-thing off to one side of the tank in an effort to give the other fish a little more room. I also added several live plants at this point, to increase the cover available for the other fish, and added a piece of driftwood to give them something on the bottom because it still looked very empty and I wanted something to give them more ground cover and refuge from the pleco. I left the plastic plants that were already in the tank there on the advice of an employee at a local big box pet store (we don't have any small aquarium stores here that I've been able to find) to help the bacterial colonies, since I'd changed out the gravel. I DID NOT change the water at all at that point, and it was very nasty for quite a while while all the stuff in the bottom settled. I changed the filter at the same time because it was disgusting, not realizing that with all the other changes I should have just let it be for a few days. I also added 2 snails at this point as a result of needing to console a 4-year-old who was extremely upset that said pet store did not sell pet dragons.
I think they were both Mystery snails, but one may have been a Nerite. I'm not sure how to tell at this point.
2. I changed their food around because I was mortified that the fish flakes were primarily corn and soy meal and food coloring. They're now getting a rotation of freeze dried brine shrimp, blood worms, and a powdered/flake/pellet food that has spirulina, krill, and a lot of other good fishy stuff in it. Everyone in the aquarium seemed much happier after a few days - the pleco stopped charging the other fish and actually came out of his cave for extended periods of time, and the tetras started exploring the rest of the tank and were generally a lot less skittish.
3. Everything seemed like it was going well for a few weeks, but the plants weren't doing particularly well. I had been topping off the tank with R/O water because we're on a private water system that has notable levels of nitrates and extremely hard water (the filter was basically fused to the back of the tank because of all the buildup and there were deposits on the back of the tank underneath it) and this didn't seem like a fantastic idea to be putting in the fish tank, given what I was reading about the nitrogen/ammonia cycles. The tank was living in my north-facing bay window, but it is back from the glass and the window doesn't get much (if any) direct sunlight, especially not at this time of the year. I decided that the decorative color-changing lights that the tank had come with were not going to work for plants, and at the same time one of the mystery snails crawled out of the back of the the not-particularly well-sealed lid and died, so I replaced the lid with a glass one that fit much more closely and swapped out the light for one that was recommended to work for plants (also by the pet-store-employee).
4. At this point I read that I should be doing regular water changes, so I started with that. I still didn't know that I needed to remineralize the R/O water or that it needed to be oxygenated before going in. I pulled about 10% of the tank water out and just replaced it with R/O water.
5. A week or so later, I did another water change, but probably changed somewhere between 25 and 30% of the water, not understanding that I needed to go much slower than that in a tank that had never had any kind of water changes before. The next morning my kids found the pleco belly-up.
6. At this point I sort of started panicking. I'd managed to kill both a snail and a pleco, and I was afraid to do anything else to the tank (although we did replace the snail because my younger daughter had picked it out and was heartbroken). I backed off on feeding the tank, worried that I'd spiked some level of something too high. I didn't realize right away the pleco may had died from the water parameters changing too rapidly due to the sudden large water change.
7. About a week after the pleco died, the tank water started turning green and there was a visible algae explosion on the sides of the tank. I took a brand new sponge to the inside of the tank and cleaned off the worst of it, and stopped turning on the aquarium lights during the day. We went back to the pet store to look at replacing the pleco, which was when I discovered that a pleco shouldn't have ever been in a 10-gallon at all given the sizes listed on the aquariums. An otocinclus was recommended, but said pet store was out at the moment, so I was told to try again later in the week when they got another shipment of fish.
8. No otocinclus came in the subsequent shipment, and at this point I was already starting to worry that the tank was borderline overstocked even with the pleco gone. I was also discovering that the plants really needed a substrate designed for a planted tank and not just gravel, as I was getting really concerned at how brown and beat-up everything looked. I also realized that the algae was starting to grow on the plants and that they needed to be cleaned off, but I was getting ever more paranoid that doing anything to the tank at this point would just make it worse.
9. Fast-forward to today. The fish have been fairly listless for the past week, although none of them have been hanging out up near the top like a lot of articles seem to say they will if the nitrates/ammonia levels are dangerously high. I ordered water testing kits that just got here. I've read that otocinclus are tricky and that water really needs to be in good condition if you want to have a good chance of them surviving and acclimating, so I more-or-less did a complete overhaul on the aquarium today to try to get the tank ready for whatever else ends up in it, or just to get it healthier for the fish that are already there. I took out all of the plants and fish, pulled all the gravel back out (did NOT wash/rinse it off, though), and took all of the water out. I wiped out the inside of the tank and scrubbed off as much of the mineral deposits as I could. Then I replaced about 2/3 of the gravel with Fluorite, added about half an inch of the other gravel back on top of it, replanted all the plants, and replaced the decoration/driftwood. I took all of the water that had been emptied out, ran it through coffee filters to get out the fish poop and everything else that had settled in the gravel (man was that disgusting), and then replaced the water back in the tank, plus about a gallon of R/O water that had been treated with about 1/8 tsp of Equilibrium. At this point I realized that in the middle of everything, I'd forgotten to rinse off the Fluorite, so the water turned a kind of reddish-brown. I let it settle for a few hours and then started re-acclimating the fish and snails to the new water, which I strung out over another hour and a half or so. I added about a tsp of Tetra Aquasafe (which I haven't been doing at water changes because the water was R/O) out of sudden worry that the unrinsed Fluorite and/or the Equilibrium may not be great for the snails. And then wondered if the Aquasafe was going to counteract the trace minerals in the Equilibrium and make the whole thing a waste of time. I was getting nervous by this point about how long the fish had been in a small container for the cleaning, so I added them back to the tank and promptly fed them, even though the water was still a bit cloudy. They seem to be doing fine now, although the water hasn't yet fully cleared. After all of the water cleaning there were only about 7 gallons of water left, including the gallon of R/O water I added.
So now for the onslaught of questions.
1. Are you supposed to use both Equilibrium and Aquasafe in conjunction with each other, or is Aquasafe bad for planted tanks? Does it lock up the trace minerals the plants need?
2. I figured the safest thing to do would be to add about a quart of the Equilibrium-treated R/O water back to the tank twice a day for the next few days, until the tank is full again, rather than filling the tank now and doing what would be the equivalent of a 40% water change when they've historically had so few water changes, the last one appears to have killed the pleco, and I'm already freaking out about overhauling the tank (again). Would this be the best way to finish refilling the tank, or should I just fill it now?
3. I was going to order an Oto, but I'm reading now that they like to be in groups of 3+. This to me feels like it's probably too many fish to add to a 10 gallon tank, but since algae is clearly going to be a problem and the snails don't seem to be keeping it in check, am I better off working up to 20-30% water changes bi-weekly and doing the 3 of them, or what? Would red cherry shrimp be a better move here, and if so, how many? Would they clean the algae off of the plants? This is my biggest concern, and the leaves on several plants are turning brown/black from the algae.
4. Is there a way to get the dust from the Fluorite out of the tank at this point? I'm really kicking myself for not remembering to rinse it off.
5. In general, can someone reassure me that I'm on the right track for taking care of these fish, or just give me general pointers on what to do/not to do? We've probably dropped close to $300 on this "easy" gifted aquarium in the process of trying to get it on track and set up for long-term enjoyment and fish health, and although I don't mind spending money on something if it will be for the improvement of fish/plants, I'm getting a little hesitant to spend anything else until I know for sure I'm on the right track - a lot of aquarium information online seems very conflicting. Mostly I just don't like seeing things that I've committed to caring for dying, and I'm getting really worried that I'm in over my head here and that I'm just going to end up with more dead fish in the next week or two.
Thanks for your patience, and any help/reassurance/pointers anyone can offer.