Let's talk about cleaning crews

[Delphinus]

Cleaner shrimp are ornamentals -- ie. there's no way you could consider those as "cleanup crew". They may jump on fish and clean out their scales or whatever, picking at parasites but even as such they would not be a substitute for proper husbandry -- it's just cool to watch.

I think that some cleanup crew serves a purpose. However it is entirely possible that the recommendations are seriously overkill. I.e., you may not need 40 or 50 snails, if you overpopulate eventually they will starve anyhow, and then you have all these empty snail shells littering the place.

In new tanks though it seems common to get a bad hair algae outbreak and if nothing eats that then it can be hard to get over. The only problem is that whatever eats that, will run out of food when it's gone, and may need to be fed. Things like sea hares are awesome for cleaning out a bad outbreak but then it's a crapshoot as to whether they'll adapt to being fed manually, or just starve out.