Build upward, not just outward
An angelfish is a deep-bodied ambush hunter shaped to slip between vertical stems, so enrichment starts with height. Tall vallisneria, broad Amazon swords and a slim, upright piece of driftwood give the fish lanes to patrol, corners to inspect and a station to hover at while it watches the room. Open horizontal caves and low ornaments do almost nothing for this species. Choose smooth, soft-edged planting - long trailing fins tear on sharp plastic - and leave one clear column of open water where the fish can turn and display. A tank that reads as a forest of verticals will keep an angelfish moving through its whole volume instead of camping in one corner.
Turn meals into hunts
Nothing wakes an angelfish up like food that behaves like prey. A few times a week, swap the usual flake for frozen or live daphnia, brine shrimp or mosquito larvae, and scatter them across the surface rather than in one spot so the fish has to quarter the tank picking them off. Between those days, vary where the staple food lands - left end one morning, right end the next - and occasionally hold a morsel at the surface so the fish rises to take it from your fingers. A predator that expects food in one corner at one time stops exploring; one that never quite knows keeps its hunting circuits switched on.
Rotate the layout in small steps
Angelfish investigate change, but they also hold territories, so renovate like a gardener, not a demolition crew. Every couple of weeks, move one plant, swing the driftwood to a new angle, or swap a stone - then watch the fish re-map its world over the following days, testing the new lane and re-drawing its boundaries. A floating plant raft that shifts the light pattern is another low-effort change they respond to. Total rescapes, by contrast, reset every territory at once and can turn a settled pair quarrelsome, so keep each edit small enough that the fish treats it as news, not upheaval.
Company and calm count as enrichment too
Activity is not only about objects. Tankmates that move gently in the middle water give an angelfish something to watch and follow, while fin-nippers and frantic species subtract activity by driving it into hiding. Keep the tank somewhere the household actually passes - these fish track people, learn feeding faces and will patrol the front glass for attention - but away from doors that bang and speakers that thump. A fish that feels secure shows the behaviour you are trying to enrich; one that feels exposed spends its energy on staying safe.
Spread the routine so it actually happens
Enrichment fails when it depends on remembering: the hunt-feed that was meant for Tuesday slides to the weekend, and the plant rotation never happens at all. It works far better as a written rhythm - a hunt-feed on set days, a single layout change on a fortnightly one, a note of which new lane the fish adopted. Listing those jobs on the angelfish's Care Teams list in KinsLe turns them into dated tasks anyone in the house can pick up, so the cichlid's interesting life continues even in the weeks you are too busy to invent it.