Help! Please Look!

I have a ~medium sized tank~ (Not sure howmuch it holds) with 7 goldfish and one pingi pingu. I clean my filter roughly every week but i keeps getting bunged up and really dirty. Also I am confused about how I should feed them. I usually feed them twice a day morning and nite with a big pinch. A few hours later they are all going crazy round the tank as if they are really hungry. Please help!!!

7 goldfish sound alot for a meduim size tank, you will have to find out how many gallons it holds, 20gal for the first goldfish, then 10gal for every other one added, do you have water stats in ammonia,nitrite,nitrate,and ph, goldfish are big waste producers, and they need an excellent filter, what filter are you using, i would suggest a water change.
Also what do you feed the fish as to many dried foods are not good for goldfish as they are prone to swim bladder epsecially the fancy variety, you need to feed frozen foods like bloodworms,brimestrimp, and daphnia which is good at digesting the fish food. Also veg is good in there diet epsecially peas,broc,cabbage, anything green.

it sounds like you have got too many fish in there, when i was keeping goldfish i fed 2 small pinches, one in the morning and again at night.
dont worry if your fish are looking frantic, they can go for days without food, but if you are worried then for peice of mind feed them three small pinches a day.
as others may have said though, goldfish are big waste producers so get a good filter that can power a tank bigger than the one you put it in.
also check nitrates and nitrites as a rule.

With the fish you have right now, you need a 100 gallon tank. A 'medium' sized tank is probably not that big. Post the dimensions. Please read the links in my signature and all the pinned topics in this forum concerning goldfish. Then consider returning at least half the goldfish to your fish store. If the filter is getting clogged up, it's because you are feeding too much and have too many fish for your tank. Increasing the frequency of water changes, finding new homes for some of the fish and reducing feedings toa pinch once a day (fish always look hungry - don't worry) should improve the situation.

Thanx very much 4 all your comments. I will consider all your messages
Thanx again.

Elfy Alex