Setting up a freshwater tank for Goldfish

Question
QUESTION: Hi Jaymie

My son is trying to set up a tank for goldish.  We bought a 30 litre (approx 7 gallon) tank new from Pets at Home, we also bought new gravel, an ornament and 3 plants.  The tank came with a Rena Superclean Filter, light, hood, and free samples of API water conditioners (Stress Coat / Stress Zyme).  

We followed the instructions, put the gravel in, the plants and ornament, put normal tapwater in, put the samples of water conditioners in, switched the filter on and hey presto - looked beautiful.  Instructions were to wait 3 weeks before putting any fish in there.

Day 2 the water went kind of cloudy.  Day 3, we noticed there were patched of milky white slimey stuff building up on the gravel.  Day 4, the slime is growing and the inside of the glass is coated in slime and it stinks when you lift the hood up!  We don't even have any fish in there yet, so we were thinking it must be from something WE have put in there.  Local pet store suggested that we put too much water conditioner in the water and we hadn't rinsed the gravel well enough.

So we started again.  Took everything out, boiled the gravel, scrubbed the ornament, cleaned the inside of the tank, washed the plants and filter casing thoroughly and put everything back in MINUS the water conditioners.  The pet store gave us a water conditioner called Safe Gguard Aquarium Water Treatment.  We calculated exactly how much we need to ensure we weren't overdoing it -  but exactly the same thing has happened.  3 days later there is the same milky white slime growing from the gravel.

I have tried surfing the net - there seems to be a lot of suggestions to say overfeeding, high amonia - but we haven't even got any fish in there yet, so there is certainly no food (other than the plants).

We have taken the plants out just to see if the tank improves, but today the slime seems to have gotten taller (i can see tendrils waving about).  

Is this normal?  We would be grateful for any advice you could give.

ANSWER: Mel,
To start, the tank is too small for a goldfish. The minimum size tank for 1 goldfish is 20 gallons. Goldfish are very messy and huge waste producers. Even the common goldfish, also known as comets or feeders can get as large as 18". If the tank is small it will stunt it's growth, but will die a very painful death. The outside of the fish will stop growing, but all the internal organs will not stop.The filter will need to be bigger than the tank. What I mean is, if the tank is 20 gallons, the filter will be for a 30 gallon tank. That being said, lets figure this out. The tank does what's called cycling. That is the cloudy water you were seeing in day two. It sounds like you cleaned everything correctly. The API water conditioner is an awesome product. Ok, back to the cycling. Everything you did was correct. During the first week, you will see the cloudy water and the first of 2 bacteria blooms. The first one is the bad one. This bacteria will kill a fish. This is when you want to start seeding the tank by feeding it fish food. This will bring on the ammonia need to cycle the tank. A week or so later comes the second bloom. This is the good one needed for your fish to be healthy. Once that bloom comes, about 2 weeks after the first one, you will want to start testing the water for ammonia, nitrites, and nitrates. Once the ammonia, and nitrites are reading at zero and the nitrates no higher than 20ppm for 5 days in a row, your tank is cycled and you can start adding fish. Everything is part of the cycle process. The tank will take 3 to 6 weeks to cycle. Let me know how it looks in a week or so. If you still see the stuff growing. Are you using live plants or fake?

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

QUESTION: Thanks for your quick reply Jaymie.

We had live plants in there - we were told by the pet store that this would help airate the water and would be a good fish food also.  We have since taken them out though, so if it's not the plants making the water slimey, I will get some more!

I am glad we haven't put any fish in the tank yet - the pet store told us we could have 4 or 5 small gold fish in that tank :-/  what fish would you suggest for a tank that size?

I am researching cycling process now - how much fish food should we put in?  

Many thanks

Mel

Answer
Mel,
You are welcome. Yes live plants are great to have in the tank, but as far as the goldfish eating them, I have never seen that. Unfortunately, most of the large pet stores do not know much about the fish and products they sell. They gave you wrong information. Goldfish, even the common goldfish, get large and the minimum size tank for 1 is 20 gallons and 10 gallons per fish added. To have 5 goldfish, the minimum size tank is 60 gallons where 100 gallons would be better. Most cold water fish get quite large so there really isn't any cold water fish you can have in a 7 gallon tank. If you want to go tropical,meaning adding a heater,the Betta, which I am partial to since I breed them, would do great in there. The only problem is, he would be the only fish that can go into the tank. They will fight with most other fish. The Betta also does not require a filter and does not need the tank to be cycled. You fill the tank, set the heater. add conditioner, wait until the water temperature is 82 degrees and add the Betta. There are many variations so I have given you a website all about the different types of Betta's. They don't need the filter for 2 reasons. 1. some of the male's fins and tails are very long making him a very slow swimmer.
2. they have whats called a labyrinth organ which allows them to come to the surface of the water and breathe the air like we do.

You will have to do the weekly water changes because there is not filter.

http://bubblesandbettas.blogspot.com/p/betta-breeds-tail-types.html