I'm happy to try and explain these inconsistencies. And believe me, if I sound condescending, it is not intended as such. This issue comes up a lot on this forum, and all of us have to learn and understand it if we want to be responsible and successful aquarists.
Right I am confused (very) I’ve seen multiple tanks 54 litres and smaller way smaller (circa 30 litres) that seem to be doing well for at least a year (that I know of) that have a massive amount of a mixture of neon tetras and guppies (like 20 fish in total, water identical to mine).
This is a prime example of the comment by Nathan Hill in blue in my signature block. You and I cannot possibly know what is going on inside the fish in terms of the operation of the fish's homeostasis. We can however learn from ichthyologists and biologists what will occur under various situations. Fish placed in situations that are somehow inappropriate for the species will not be in good health, guaranteed. At the very least they will live a shorter than expected lifespan (I pointed out in another thread earlier this week about the normal lifespans of small fish being considerably longer than many think, and this is related--tetras should live years, not months, but not in such conditions), but at the worse they will be subject to all sorts of debilitating and possibly fatal health issues due to the weakened immune system (always a first result of any stress) and general physiological weakening.
Second point on this is advice and who gives it. Several of us on this forum have considerable experience and in some cases biological training. At the very least, speaking for myself, I have researched so extensively over several years that I learned the sources that are reliable and those that are not. Following the guidelines of those true experts means we will have more success with fewer failures, and healthy fish. Which I hope is the goal of all of us.
Both my LFS and Pets at home, my local pet shops, seem to think even a 4 inch fancy gold fish can be kept with 4 danios With no issues?!
Any store that thinks this is a store not to trust, ever. Goldfish are stand-alone, and no goldfish authority will tell you any different. Consider it like a store telling you evolution is a hoax; we know from the indisputable scientific evidence that evolution not only led all species to the present, but it is continuing today with many of our aquarium fish in their habitats, evolving into new species. Trusting the scientific community makes sense; relying on anything else does not, because it is conjecture, risk, experiment...and that is no way to keep living creatures.
There must be something other than Nano fish and Bettas, I can keep in a 54 litre tank?
What about one balloon ram sized fish and tetras?
Early on 10g was mentioned, and I went with that, not noticing the liter was not equivalent, my fault. A 54 liter is 14 gallons (US), and if this is 24 inches (60 cm) in length, that is a different proposition. Though having kept and spawned the blue ram, I would not recommend subjecting it to this small a space, but consider at least a 30-inch (75 cm) 29g tank minimum for the ram pair. Suitable dither fish would work.
EDIT: Just occurred to me that I missed the temperature issue talking about rams previously. This fish needs warmth, 80F or higher. There are many tetras that cannot tolerate this long-term, so another consideration.
