I agree with others that find them very aggressive as adults, in anything under a 6 ft tank, and even in that size tank can be relentless as adults.
They need lots of sight blocks in the form of rocks, logs and aquatic vegetation, your first pic shows about half (or less) sight breaks than I would use.
Being so colorful, they are very easy to see by birds of prey in nature, so although they are aggressive, they can also be shy, if not enough cover is not provided. so surface vegetation in the form of floating plants or lily pads, or overhanging terrestrial vegetation like your Pothos should is perfect.