Hello Everyone

Hi Everyone my name is Russ and i am a total novice at fish keeping. I am learning the hard way at the moment as we went out and brought a smallish tank which has 6 harlequin Rasboras in that are doing fine.

We then decided we wanted more so have brought a Juwel Rio 180 which is going through a fish less cycle. photo Attached

Welcome, Russ

Glad that the harlequin rasbora are doing fine; assuming from what you write that you didn't do a fishless cycle with them, then keep monitoring water quality (ammonia, nitrite, nitrate) regularly, and that should keep you/them right. I have harlies too - lovely fish.

Great re the larger tank - it is very impressive, so you must be a natural aquascaper. That larger tank will indeed give you more options. All the best with the fishless cycle - the guide on this website should keep you right. Any thoughts yet on what fish to have in it?

 

When you say you did a fishless cycle on the small tank for 2 weeks, did you just let it run or did you add ammonia? And are you adding ammonia to the new 180 litre? Pets@Home would never have mentioned cycling 

Something you could consider, if you can source them, is 6 standard cherry barbs and 6 albinos (orange males, yellow females, both with red eyes) That would give you a big shoal of cherry barbs that looks like 2 shoals of different fish. Fish behave more naturally in bigger numbers 
I am a covert to the 'lots of individuals of few species' rather than the 'minimum numbers of lots of species' method of stocking 

Ahhh, that is not fishless cycling, I'm afraid. Even if it contained the right species of bacteria, without adding ammonia the bacteria won't multiply. You need to add ammonia either made by fish (technically that is still fish-in cycling) or from a bottle. Using bottled bacteria without ammonia doesn't cycle the tank.

The most highly recommended bottled bacteria products are Dr Tim's One & Only (which is hard to come by in the UK) and Tetra Safe Start. Both of these contain the right species of nitrite eaters, and the use of this species is copyrighted so no other product contains them. But even they do not cycle a tank instantly and the bacteria need to be fed ammonia.

However, your tank looks to be fairly well planted, and plants use ammonia as fertiliser. Provided you take it slowly and monitor the ammonia and nitrite levels daily - and do water changes if you see either above zero - you might get away without cycling the tank.

You will need to add ammonia with Dr Tims. The company recommends ammonium chloride rather than ammonia but ammonia will work just as well.
Or add fish a few at a time.

Here is the method for fishless cycling https://forums.thinkfish.co.uk/fishtank-filtration-and-cycling/fishless-cycling-how-to-do-it/ but with live plants in the tank the first dose should be 2 ppm not 3 as a lot of plants don't like it that high.





What are your plans for the small tank? If you don't intend keeping any fish in it in the short term, you could move the fish and all the filter media into the 180 litre, add Dr Tims and stock slowly. Since you don't actually need the carbon pad (the black one) you could replace it with the media from the smaller tank. Then once the 180 was fully stocked, you could always move the media back into the smaller tank if you do want to keep fish in that one.

Think of the fish and filter media as paired. They should move together, within a few hours of each other. Move both across and wait a few days for the fish to settle. Then I would get a few more harlequins, test every day for ammonia and nitrite and if they stay at zero for a week, get a few more, and so on till you have all the harlequins you want. Then add cherry barbs the same way. Add the Dr Tim's when you get it, that should help (provided it hasn't got too hot or too cold on its journey to your house).
Once you have enough barbs, get the cories; by now there should be enough fish in the tank = enough bacteria to get all the cories at once.
Once you have the cories you'll need to add a meat (fish or shrimp) based sinking pellet to the food as they won't do well on flake. Cherry barbs are very good at picking over the floor of the tank looking for bits of food so they'll clear any left over flake. I used to have some 

Leave the otos until the tank has been running long enough to grow some algae. Bns will eat other things besides algae so that could be added sooner.
It is common for otos to just die shortly after being added to a tank. There are two reasons - not enough food in the tank, and they way they are treated before you buy them. Always wait until they've been in the shop for at least 2 weeks so the weak ones will already have died, and choose the individuals with rounded bellies as that shows they are eating properly.