what should I do with my pearl scale.

Question
I have a 180 litre community tank with 2 commets, 2 fantails, 1 black moore, 1 orando, 1 pleco and a pearlscale.  I know that the commets should not be with the other fish I was ill informed at the pet shop and did not realise they were commets.  All the fancy fish seem to be holding their own and eating well appart from the pearlscale.  My dilema is I have another tank (only a small starter tank) but I am wondering if she will be best keeping in the large tank or moved to the small tank by herself.  She does not move around and hides in the back of the tank I have not seen her eat yet, i have been using a variety of food and making sure there is some next to her but she does not attempt to take any.  I have been to two different pet shops, one told me to move her one told me to leave her.

Answer
Hello Ellen,
First thing's first, according to you, you have a 47.5 gallon tank. I go by gallons, because it is much easier for me to tell how large the tank actually is. But 180 liters translates to about 47.5.
Anyway, that is a little small for how many fish you have. The best way to gauge it, and to be sure your fish have enough room for swimming and living, you want to have 20 gallons for the first goldfish, and ten gallons extra for each goldfish thereafter. This is a rule developed specifically for goldfish, to ensure that the fish is able to have a minimum of the space they need, and the water to dilute the massive amounts of ammonia that goldfish produce.
Based on these calculations, you should have at least a 100 gallon tank.
If you are wondering how this would make a difference, let me start off by saying that when it comes to aquariums, bigger is ALWAYS better.
I recommend you do some studying on the Nitrogen Cycle (you can probably just Google it) so that you can learn more about keeping fish and why it's so important that they have large enough tanks, that they get enough water changes, and that you don't add fish until your tank has been established (gone through the cycle).
So, basically, you do not want to put your goldfish into an even smaller tank. In all honesty, it would be best for you to either buy a few 20 gallon tanks and disperse the fish so that they have proper tank sizes, or upgrade to a 100 gallon tank, so they can all liver together properly.
Don't forget, you'll need to have at least 55 gallons anyway because of your pleco - they grow to over 2 feet long.
They may not seem large now, but your fish will grow. And it is imperative that when putting fish into a tank, you account for their adult size, not the size they are when you buy them.
For the moment, it would be a good idea to get your water tested, and see what the ammonia, nitrite and nitrate levels are (you will know and understand what these are and why they are important when you study the Nitrogen Cycle) not in toxic levels. If so, you'll need to perform a water change straight away.
You can google water changes and learn more about why those are important as well.
Thanks for asking for help, and best of luck to you.