I would sort your current stocking out first, you have a couple of fish in low numbers and others that are not really suitable.
I think I would get your tank to this kind of situation first
2 - 3 pearl gourami (1m 2f) - use your judgement if you think the two you have will remain calm enough but sometimes 1 female can be pestered to much by one male...
1 Angel or 10 Neon Tetras
8 Julii Cory
Is personally what I would do with this tank.
The first thing is the Angel and the Neons - Angels eat Neons its a fact at some point the Angel will get large enough so I would choose between them - I think the Angels and Gourami could co-exist in this tank - though again use your judgement if issues occur as they grow and mature.
The GBR needs to be in a tank with a higher temperature than the other fish
As you know the pleco will outgrow the tank.
The Guppies, for me personal preference if you are in the situation where your happy to rehome fish to get a better balance I would have a bit of a shuffle but that said they can be problematic in a tank, their big flapping tails can get nipped especially when you have other top dwelling fish and territorial ones at that. So could be practical as well...
The Blind Cave Fish, quite a big fish for this tank when adults and need a decent sized school. They wouldnt be my first choice for this tank because of this....
Then it comes to the Cories and Neons (if you chose the Neons)I would up the schools of these to 10 and 8 bigger schools are always better and a larger number makes more of a spectacle of the fish as they swim around in one group they will be more confident and show much more colour.
If your on the fence about the Black Widows for more colour there are better options as well.
Sorry to be so harsh but it sounds like your in the position to be rethinking your stocking for a long term healthy, colourful tank.
Long term stocking for me would be
3 Pearl Gourami - 1m 2f
3 Swordtails or Platies - any colour, any mix - 1m2f
8 Dwarf Neon Rainbows
10 Neon Tetras
8 Julii Cories
3 Red Lizard Whiptails (LDA010)
I think this would be a big splash of colour in a lot of groups - I left the Angel out as it could cause issues but its upto you but I think it would be in place of something else like the Whiptails or Livebearers. The Dwarf Neon Rainbows are always a great splash of bright blue and next to Neon Tetras I always think they look great - the colours look fantastic and the shape variance really gives the tank a good dynamic. I would decorate the tank with tall rocks and large leafy plants like a big Anubias and Amazon Swords.
Hope thats helped, hope you dont mind my suggestions but I would seriously consider looking at some of the stock you have at the moment...
Wills
