Newbie Questions

Hello you guys.
Actually I am not a complete newbie as I kept fishes 30 years ago  .As far as I can see now it is a lot more scientific than it was and I must say  I am very much confused.
Basically I want to  keep Angelfish and I will start a 100 liters tank because it comes free ::-] I just want to keep angels, maybe little some company (any suggestions??) and I want to breed them later with a larger tank.
As I will get a hand-me-down tank with a few goldfish I don't know whether I need to change all substrate ,or just to keep them as they as ( obviously minus existing inhabitants).Do I need to cycle the tank before putting angels or just add them as tank and filter in use for long time.
Anyway these are first questions come up my mind now.
Thanks for all replies in advance.

Hi Dragut,

Welcome back to the hobby. I am a similar returnee after keeping fancy goldfish in what I would now describe as a tiny tank. When you say the hobby is far more scientific now I think that may be just down to good information being more readily accessible. I bet even 30 years ago there were some stellar fishkeepers who understood the importance of the nitrogen cycle, etc. Only 5 years ago I thought I was doing a great job scrubbing out the tank once a month and washing the filter in untreated tap water. After reading just a few articles on the web I would now never dream of doing such a thing!

Given that you've taken the time to read up on fishkeeping before buying your fish is a good indicator that you're sensible and likely to be a successful fishkeeper. When I was restarting the hobby, the best bit of advice I read was "If you look after the water, the fish will look after  themselves". Whilst this isn't 100% foolproof, its a great start. Angelfish prefer softer acidic water, so I'd check your water to see that it is favourable. You know that fishless cycling is the way to go and it sounds like you're inheriting an establish filter. From a purely cycling point of view, I think its best to keep as much filter media and substrate from the existing tank as possible to help maintain the bacteria. Sanjo is right, goldfish are incredibly messy fish, but this should mean the bacterial colony is well established. I'd do an almost complete water change and try to vacuum as much crud out of the substrate as possible. Scrub the inside of the glass if necessary, but don't use any chemicals or cleaning apparatus (sponges, brushes, etc) that have been used before. Unless you're feeding the tank ammonia, don't leave it too long before adding a couple of fish as the bacteria will die back. If you don't fancy adding ammonia, I would start with two angelfish for the first month and then add another one or two every month over a 6 month period in order for the tank to fully establish.

My only concern is that there may be diseases within the existing tank, however if the goldfish are healthy then I wouldn't be too concerned with this. It seems to me that there are so many ways of introducing disease to the tank accidentally its just part and parcel of fishkeeping.

Now angelfish prefer taller aquariums and the thinkfish profile recommends a length of at least 90cm. With a 100ltr tank with an internal filter, that equates to 10 angelfish maximum. If you want to keep other fish types you'll have to reduce the number of angels. Small (non-fin nipping) tetra would do well with angels. Neons, cardinals and rummynose spring to mind, but there's a whole host of possibilities. Cories would also work well. Use the community creator and find your best combination.

I'd also plant the tank heavily as angels love vegetation. I always think vallisneria works well with angelfish, but that's a personal preference. 

I'm sure you'll get plenty more opinions here soon, but good luck with it all!

Well I guess neons would be a terrible choice as tankmates go... but it could be very interesting to watch!

I don't know anything about the colour types of angel as I've never had a tank tall enough to keep them. Is the seller keeping them till you have the tank ready? If it is just the angels to start with, they won't need a lot of bacteria in the filter compared to a fully stocked tank so even if you lose some during the set up process you should still have enough.
Angels can be kept alone, in a group or in a known pair - that is a pair that have bred before. The ebay description sounds like a pair that have just formed.

Once the fish arrive, you do need to keep an eye on the tank water until you are sure it is OK. You need to test for ammonia and nitrite every day till you are sure they are staying at zero. If you haven't got a test kit yet, the type with liquid reagents are better than strip ones.

The ebay description says the angels are still small. In this case, the sooner you get tank mates the better, water stats permitting. Angels are territorial and can object to later additions. And as fish in shops tend to be young, and therefore small, they are more likely to be eaten by fully grown angels before they have chance to grow - get them while the angels are too small to eat them. Test for a few days every time you get new fish.
If at any stage you have a reading above zero for ammonia and/or nitrite, you need to do a water change to get them down. And don't get more fish till the readings have been zero for at least a week.
Is this the new scientific way of doing things?