Yes to tap safe. Yes to gravel cleaner and I've been doing x2 water changes a week minimum. I don't like seeing the glass mucky and also don't like seeing the tritus. I've also got 3 sachets of purigen in one of the canister filters. Temp 27 degrees.
I don't want to loose the dat and love all my new world cichlids. Would be probably wise to loose the angel fish and discuss. Love discuss thoe.
Looking at a new tank with at least 500 litres volume?
Also thinking about swapping out a canister for an oase bio 850?
So really great that you do that much maintenance
hopefully we can get it to a point where it can drop to.
Filtration wise I would look at getting either big Ehiem filters or Fluval FX6's. The Oase are good to a point but with big beasts like this you just want pure power which the FX6s would do and they are cheaper than the Oase.
If a bigger tank is on the cards go as big as you can if you want to keep the Dat, I agree with Colin that a 6x2x2 should be the absolute minimum but a 7 or 8 foot tank would certainly not be over kill.
Its an old thread and unfortunately some of the images and links are dead but this gives an idea of what a full grown datanoid is capable of looking like
https://www.fishforums.net/threads/1000-us-gal-project.318731/
After a bit of a google and putting a random Barnsley postcode into the yorkshire water site I am fairly confident you will have soft water, around 8-9gh. So I would be focusing on the South American fish you have and its good news on that front for the Dat, which is really important for such a big animal. But it does mean I would prioritise rehoming your Central American cichlids like the Lyonsi, Nicaraguan and Jack Dempsey.
For me if we can push the boat out to a 7x2x2 with 2 FX6 filters thats the starting point with a Dat for me. I've just added this picture as a bit of context, this is a big animal that needs to be kept properly and kept with fish on the understanding it is a predator so we need to be thinking of fish that are at least half its adult size so tank mates need to be able to grow over 9 inches long.
For tank mates I would try and get some more Leporinus, they are a bit rare but they are also often rehomed because of the issues but if you have a tank big enough a small group of about 4 would make sense and they would focus on each other naturally and ease any stress on other fish. Your Severum is going to be a good candidate to stay, they are going to be dinner plate sized and you could consider more Severums, maybe some other big South American Cichlids like Oscars, Festae, Geophagus Brasiliensis could work?
Long term I'm not comfortable with your Gourami or Catfish being with them as they are only 5-6 inch fish so I think they could end up as food. You can see in this picture of a youngster how big their mouths truely are. They are ambush predators so would just wait for the other fish to lurk by and suddenly their huge mouth would just envelope the fish.
Past that its really down to you and what you want to do with your tank and fish, whats the biggest tank you want to go to? Which fish most excite you, I know its mainly the Dat and New Worlds but we need to work out numbers and what the community looks like.
Wills