stock level/clown plec and platy

Question
Hello Karen,
ive a few questions regarding my tank and its inhabitants.
Firstly, i have 210 litre tank, that has about 15 plants,smallish size as i recently did a bit of gardening as they were growing like mad!I have several rocks and some planted driftwood.In this tank i have 2 corys,4 platies,6 mollies,one of which is 4 inches,others are about 2 inches, and 2 are babies.I have 5 neon tetras and 5 rasboras,4 rainbows and 2 clown plecs(about an inch long)
I realise some of these are incompatable,but i lost a tank due to a move and a stress crack.They seem happy enough.I have quite a high ph, which i was told by a local acquatic shop that our water is high in ph.im considering using some r.o water.We also have nitrates in our water as its an agricultural area.I have a rena canister filter with two types of sponge,zeolite and carbon, and im going to put a rechargable nitrate remover in.My nitrates measure at 50.Thats the background info!
I would like to know what stocking levels i should have.Can i have any more fish,and what would you recommend?id like bigger fish, but i dont want anything to eat my tetras.
Secondly,i had a platy that died about a year ago.he had a growth on his side and some of his scales looked paler and shiny,like spilled wax.I kept my watchful eye, and nobody else got it. However, ive got another platy that has the wax stuff, but no growth.hes swimming and greedy,and noone else has it.it is slowly growing though.what is this and what should i do?
Lastly, i bought 2 clown plecs a week ago.I have algae and i thought they may like to clear it up for me,although the algae i have looks like fur.
i have seen one,but cannot find the other one.i dont want to take everything out as it may stress them.I read that when they die,and they die easily,they quickly form a bacteria soup, that can wipe out a tank.Obviously im concerned as ive not had a plec before.Also, in this article they said that once a plec stops eating it wont start again. how do i know they are even eating as they dont come out at feeding time.I feed a plec wafer at night in a dark tank.My corys will probably eat that as they are quite lively!I feed broccoli for my mollies,and have dropped in a tinned green bean(which i also read about)i think my male molly whose a greedy bully would have that!
If you have any advice for me,that would be great.I adore my fish and want to do the right thing to make sure they are all happy and healthy.
Many thanks Karen,sorry this is a mini novel!
Lisa

Answer
Hello Lisa, it sounds as if your 210 liter/55gal aquarium is well stocked with a wide variety of interesting species. Actually, most of these fish are compatible in general. I wish I knew how 'high' your pH actually is. The real fact about pH is it actually isn't all that important to keep it at a specific level. Most fish do absolutely fine in less than ideal water. The fish adapt to less than preferred water chemistry, even to the point of soft water species spawning in hard water. This has been proven countless times... I myself don't bother with pH, simply because it's a fact that trying to alter the pH all the time is too risky and not worth it. It can do more harm than good too. And also it is usually not neccessary. The most important thing to watch for is are your fish doing fine and are they very healthy with vibrant colors and finnage? R.O water is a good way, however, to mix with tap water to a specific pH. But it may become such a chore you may wish you hadn't gotten it started. But it's Ok and fine if you are willing to use it. ;-)Just remember that fish thrive in a stable not specific water chemistry.~
The reason for me not recommending altering the pH is when you add chemical pH risers or powders. These work---for a while, but your natural buffers in your tap water will raise the pH in not time and your fish are in constant subject to a flucuating pH and you will end up with very stressed fish. My best advice is to do nothing but give your fish clean water with plenty of frequent water changes to remove pollution buildup.
As for your high nitrate level in your tap water...Hmmm...I've never had that problem. But my first thought is to use a water conditioner which neutralizes or removes nitrate such as PRIME or AMQUEL. Using one of these with your regular water changes should help with any bad effects of nitrate. If I come up with anymore info about solutions to nitrates in your tap, I will email it to you.
Knowing how many fish to stock in your aquarium is always uncertain. There is really no way to really 'know' how many fish you are able to keep. The one inch per gallon rule isn't reliable. As ten-1 inch fish such as neons are no where comparable to One- 10 inch Oscar. The body mass is different--and it best applies only to small, skinny bodied fish like tetras. I am afraid to say your aquarium is pretty well stocked with fish. We don't want to go overboard here. But if you keep up with water changes consistantly, you should be able to add more fish. Like building up a bigger school of your tetras and rasboras to about 8-10 per school would make them very happy and be more interesting to watch as they school.
Gouramis are a larger interesting fish that you may want to consider. I'm not sure if they would be safe around your neons but if your neons are matured I would call it pretty safe. Three-spot, gold, Opaline, are all the same species but are just different color variations. Moonlight and pearls are also very pretty and good community fish for the most part. Pearls are more peaceful but also quite timid so they need lots of plant cover, particularly some thick floating plants. Your tank--already planted, should provide some decent cover for this sensitive species
Some of the larger barbs may be suitable. Don't opt for Tinfoil barbs, they grow far to large for all but the largest tanks and they need to school. Gold barbs are very beautiful, as are cherries, rosy barbs and checkered barbs.
Please research any new speices before introducing them to your aquarium. It would also be great if you could quarantine your new arrivals for at least 1-2 weeks to insure they don't have a hidden illness.
~Clown Plecostomus are a somewhat secretive species. In nature, they spend much of their time hiding in the root structures and driftwood dams. Their coloration can make them not easy to spot in the wild. The clown pleco is best for people who do not mind not seeing their fish every day. As the clown spends lots of his time hiding. The clown pleco is also a wood eater--so driftwood is always a must for this species. They are territorial and stake out claims in certain parts of their tanks a patch of substrate, especially at feeding time. Vegetables such as Zucchinni, sweet potato, cucumbers, ect...are required. As are sinking pellets and algae wafers. Providing your plecos with lots of branch-like driftwood and shady retreats where you might be able to view them also might be an idea. I suspect your other Pleco is just hiding in the tank but you do need to inspect around every corner. Look from the top of the aquarium, to the far back corners and even use a mirror if you have to to check crevices at the back of the aquarium for your 'lost pleco' to make sure he isn't gone forever. A starved pleco is generally a very skinny and miserable one. But a full, well smoothed body indicated a healthy algae eater. Clowns should help with some of your algae problems but I am not sure about hair. Siamese Algae eaters have been known for taking care of that job.

Sounds like your platy trouble might be a parasite or a sign of poor water quality. I wish I had more info on their symptoms and more to further help. Does your current platy exhibit any other symptoms. Is it their color that is faded or is there a strange slimy coating on his skin?
Anything else unusual please note it and I will further try to help!

I really hope this helps! If i've missed anything or if you have anymore questions, feel free to email me...

Best wishes,
Happy fishkeeping!
Karen~