How to cycle a tank using the media from another tank?

[Marne]

Hiya, picked up a tank today at a carboot sale, have set it up and have taken half the media/sponge out of the filter in my other tank (so both tanks have 50% of the old sponge and 50% new). How long will it take before i can put fish into the new tank?

Also any ideas on what to put in a 50ltr tank? its going to be my dd1's tank (have set it up in her room) so needs to be something fun. She wants to breed something but not sure if its big enough really (we have another tank we can use as a birthing pool .

We have guppies and 3 baby molllies in our other tank, was thinking of putting the 3 baby mollies into the new tank until they are bigger. Dd1 would like to breed guppies or mollies (but probably not enough room?). Any ideas?

we are successfully (accidentally) breeding Platys....even without a breeding tank.

they are pretty and many coloured...daughter has "trained" them to come at a whistle by associating it with feeding

I am a complete novice but my local expert suggested at least 10 days before even bothering to test water in the new ttank colonised as you describe.

Thanks foolon, i have googled 'cycling a tank using media from another tank' and have come up with lots of answers, some people saying it will be cycled within a few hours and others saying a few weeks. I'm not in a rush to put fish in (unless i need to put the baby mollies in from the other tank), i will keep testing it. Should i be adding fish food during the cycle?

My other tank wasn't realy cycled properly as i had to move fish from a tiny tank (as they were dying) into the bigger tank in a hurry, the tank was only on week 2 of its cycle but luckily the fish (guppies) were ok.

It's not the tank that cycles, it's the filter so if you moved over a filter from an old tank to a new tank then it would be ready for fish right away, providing you had the same amount and type of fish.

If you moved over half the media from your filter then you could have half the amount of fish in there, or slightly more and just keep an eye on the levels, an ammonia spike will happen within a couple of days so you'll need to test regularly. Have you been feeding the filter while the tank's been empty? You'll get bacteria die-off if there's no source of ammonia.

50 litres is a small tank but endlers are small fish and will be a perfect breeding project for your DD- as long as you've got somewhere to rehome the babies to, because they are livebearers so you'll end up with loads of them. Platys too big for a 50 litre really.

Thanks Eau, i will feed the filter until we put fish into it. I tested it last night and all seems ok appart from one thing, test kit is telling me to add 'tap safe' but i have already done this when filling it up, does this meen i nedd to add more? (i added the correct amount for the size of the tank). So i should be able to put some fish in? it will be empty for a few days whilst we decide what to put in. If we put the 3 baby mollies in there that wont be enough will it? (as they are very very tiny at the moment), should we just stick a few guppies in there and then move them to the other tank once we have decided what to put in the new tank? my other tank only has the 5 guppies at the moment and the baby mollies.

The bacteria will adjust to how many fish are in there and how much you feed them.

Why is the test kit telling you to add tap safe? If the water was dechlorinated when you added it then it should be fine.

Have you been feeding the filter since you moved over the filter media? The bacteria will die off really quickly without a source of food. Have you tried just bunging in some ammonia and testing to see what happens? If you calculate how much you need to make the level 4ppm then that should tell you how the filter is functioning.

Thank you, i have been puting food into the empty tank, i dont have any ammonia. I could go and get some fish today? was just worried about doing it too soon.

Just tested it again and all is ok, it was the Cl2 that was telling me to add tap safe but now its testing ok.

Well we bought 3 female guppies, put them in the tank for a few hours and then added one of our finest male guppies , went to put male guppy in the tank and spoted a baby fish in the tank (the new tank), so what is this baby fish? a baby guppy? seems like it may have come with the females, its tiny but happily swimming around the tank. Will it get eaten?

Could be that one of the females was pregnant when you bought them, or maybe the baby came from the shop. They can store sperm for a couple of months so they can just pop out babies even if they haven't been near a male for a while.

I can only see one baby, wouldn't there be more if she had given birth (unless the others are hiding). Dd1 is very excited about the baby, just worried it will be gone by the morning though theres plenty of room and places for it to hide.