So I was just randomly checking aquarium books from the library and I grabbed this ancient book. Pros: pretty high tech for an old book. Cons: Wow this is going to be long. First of all quoting from this section called Paradise Fish: A coution should be sounded about mixing the Paradise Fish with goldfish: (no duh) if they are not in a large pool, keep them separated. No they should not be together at all. Here is their reason for it not being with them: The Paradise Fish seem to be jealous of the goldfish's flowing fins and they see to it that they do not stay flowing very long. First of all: this shows that back then they actually thought tropical fish could be kept with goldfish! Here is another part of the paradise fish section: Temperature as low as 50 degrees F and as high as 90 F seem to have little effect on their well being, though temperature and environmental conditions do affect their breeding habits. The book also lists Texas Cichlids as 'peaceful' (wow I wonder how many community tanks this ruined) Overall I just thought it would be interesting to share about a 1968 aquarium book and how things have changed since then. I encourage you to write about any strange advice some aquarium books have given you.