What tank size would be the minimum for these fish together
 

What tank size would be the minimum for these fish together. 4 Silver Dollars,4 Angels,1 Pleco,1 Black ghost knife fish.:-)

75g might be doable.. I'd still recommend a 125+ though.

Considering the knifefish, I would say much larger. This fish will attain close to 2 feet, and being inflexible it requires an aquarium that is at the very least 2 feet in width (front to back) plus 5 feet in length. The fish needs space to turn around.

What about Length 150cm,width 60cm,height 40cm. that's 360liters/ 95gal.

You need to increase the number on the silver dollars by at least one, preferably more.

With respect to the knifefish, this would work well.

A suggestion on the other fish: angelfish would be ideal, a group of 5-7. I would myself leave out the Silver Dollars. For one thing, they are vegetarian, and I strongly recommend floating plants for the knifefish and the angelfish. Believe me, floating plants make a vast difference to both species. But being tender plants, they would get munched on by the vegetarian Silver Dollars.

Angelfish do very well in tanks with substrate-rooted plants like swords, Vallisneria, etc., which is why SD's are not good companions then either. But as the dim light here will make submersed plants difficult, I would suggest a more authentic Amazonian biotope with lots of wood branches and bogwood, a sand substrate, and then thick floating plant cover. This would be very authentic, and the knifefish and angelfish would be very happy and relaxed--which means healthy.:-)

Substrate fish like the pleco, perhaps a couple of Whiptail Catfish, are fine. On the pleco, don't go for a vegetarian species like Bristlenose, since algae will be minimal. The Hypancistrus species are primarily carnivorous, and there are so many beautiful species entering the hobby these days.

Byron.

I all ready have all these fish except the 4 angels I have 2. I have a lot of fish. have you checked out my tanks. The pleco is a common.

That brings up some another issue. Adding angels to an existing group or pair is not always workable. If the two are female, this cold work better; but if one of them is a male, he will consider the tank "his" and newcomers might not be welcomed. This doesn't always occur, but it does more than it doesn't. Angels should always be acquired together when it is a group for this reason. Now, setting up a new environment can sometimes alleviate thee issue, if the angelfish are all added to that environment together.

My previous comments on the Silver Dollar stand, regardless of circumstances. I would find them a different tank and not combine them with knifefish and angels. And before it is said, if this is already done (together in another smaller tank), that doesn't change anything; the reasons mentioned previously still apply, and going forward I would make things better for the fish.

The pleco will be OK in the larger tank with the others. You are probably aware of the significant waste issue.

I now, I bought 5 angels but sadly 3 died. what if I took them out be fore I ad the other's .

the silver's are not in the tank yet there stile in my 8gal.

Yes I am aware about the waste, my filter filter's a 1000liters a our.

As I said, changing their environment sometimes works. If you go this route, I would first set up the big tank, lots of wood branches, bogwood, etc., and floating plants. Then acquire the new angels (try to get fish that are about the same physical size as the existing) and put them in the new tank and immediately move the two existing angels in. Then hope it works.

Make sure there is plenty of hiding spots with bits of wood for the knifefish, then add it.

Obviously the tank will be "new" so seeding it with bacteria is recommended when the first fish go in; I do this via wood from an existing tank. And of course plants, in your case they will be floating. Lots of them. You won't have cycling issues this way.

Byron.