Hi Glenn, and welcome to Loaches Online.
Your proposed tank is a very nice size, but to keep Botiine loaches sucessfully, you'll need to 'up' the filtration you plan for it.
The ratings that the manufacturers state for their filters are the maximum amount of water they are able to handle and this would be for a very lightly stocked aquarium. The more fish you have, the lower that rating would become. In our shop, as a general rule, we tend to recommend half-rating what the maunfacturers claim. I believe the Eheim Professionel II 2028 is rated for a 600 litre aquarium - this is already not enough filtration for your 800 litre tank, especially when you consider proposed stocking levels, and the fact that Botiine loaches like very clean water and a lot of flow. I'd suggest using two of these models at the very
least.
There are additional benefits of having more than one filter on the tank too. Firstly, you are able to carry out maintenance on one filter at a time, to minimise disturbing all the filter bacteria in one go. You've also got the peace of mind that if one should fail for some reason (although not likely with Eheim models) you have some kind of back up with the other one.
The loaches will certainly appreciate the flow produced by these filters, and you'll also want to consider adding a powerhead (or two) to increase circulation even further - you will see the obvious enjoyment on their part.
As Gary mentioned earlier, my Clown tank is 1000 litres, and it is filtered by 3 Eheims externals, which have a combined total rating of 3000 litres (2 Professionel 3's rated at 1200 litres each, and one 600 litre filter). In addition to this we have two large Aquaclear 4000 powerheads on the tank, one at either end. The water is visibly churning with all the current, and the loaches (being river fish) absolutely love it.
With regards to your proposed fish stock list, personally I would pass on the Yo-yos. Many people do keep them quite successfully with clowns, but they can be quite fiesty, and I wouldn't like to see them harrassing my clowns. It is up to you of course, I am just saying what I think. Because it is quite a large tank you do have to think very carefully about what you put in there, as it would be a total nightmare to then have to try and remove any fish that are not 'getting on'. We had this scenario with a group of
Botia dario that we added to our tank a couple of years ago. There were 13 of them, and they created utter havoc with the clowns. Eventually, we had to remove them, and it took the best part of a day, removing all the decor (not easy with a huge amount of XL bogwood) and plants, draining the tank down to an acceptable level (to make it easier to catch them), and then the actual catching process which did upset the clowns. Anyway, this is just to illustrate how difficult it can be if you put the 'wrong' fish into a tank of that size - it is a lot more difficult to catch them out, and causes a huge amount of stress on the fish, no matter how careful you are.
With regards to the other fish, hatchets would be fine, although can jump very easily (make sure you have a tight fitting hood). They will occupy the very upper level of the tank, and so the mid-water and upper levels may look a little 'empty'. I'd suggest having a look at some Asian fish such as barbs and danios.
Good luck,
Emma
