Is a dash of salt in fresh water anquarium beneficial?

Question
QUESTION: I set up my 20-Gallon Tank on April 12.Between 4/15 to 4/25 have stocked 5 goldfish (were feeders at the time) plus 4 albino cories and 5 clown loaches. Tank is being filtered by three (3) Aqua Filters model 30. I replace 25% of water every week, replace 90% of water every 6 weeks. Maintaining filters every week, replacing them gradually every 3 weeks. Feeding them once a day with TETRAFIN PLUS Goldfish flakes plus bottom feeder sinking shrimp pellets. Every other day I add Freeze Dried worms. Using silk plants. All 14 fish seem to be getting along fine and are all the original stock. Have no heater. Need your help with following 2 questions: A-Thinking of getting 1 or 2 more tropical fish. What kind will be compatible with the ones I have? B- Someone had mentioned that it would be beneficial if I used a dash of salt every now and then. Is that true?

ANSWER: Hi Dimitri;

I really hate to tell you this but... your tank is actually already very overstocked. A 20 gallon tank is just the right size for two goldfish because they grow VERY large (8 to 10 inches) and are pretty messy. All the others in there are the "overstock" part. Clown loaches also get pretty big (a foot long) and need a minimum of 75 gallons eventually, usually in less than a couple of years. Clowns are also tropical fish that need a water temperature of 76f or higher all the time. Goldfish need it lower at about 68f. They all may 'seem' to be okay right now, but they will experience problems eventually and I fear it will be soon for your fish. As they grow larger, the danger looms even closer die to their waste production. Monitor the ammonia, nitrite, nitrate and pH levels. These readings will give you a better picture of what's going on in there so you can act before it's too late.

As for salt, your fish are fresh water so they don't require it. It should only be used to help when there is actually a problem such as nitrite poisoning, parasites, or other disease.

I am glad things seem okay for now, I just wanted you to know what could happen. Let me know if I can help you more...

At Your Service;
Chris Robbins

---------- FOLLOW-UP ----------

QUESTION: Thanks for quick response. Much appreciated. Will you still be "pessimistic" if I told you that the water is always sparkling clear and with the 3 Aqua-30 filters (all operating at the same time) plus the air-stone the tank looks very much alive. I do appreciate your expert opinion and I will plan for a 75 gallon tank. Thanks again.

Answer
Hi Dimitri;

Well, maybe not so much pessimistic, but wanting you to realize that there are serious potential problems in your tank. Looks can be deceiving. It's just better to be aware than have a disaster on your hands that you didn't anticipate and don't know how to handle. I do hope everything remains okay and hope you can get a bigger tank soon. ;-)

At Your Service;
Chris Robbins