Bloodmeal is no doubt the safest
and most biologically appropriate source of iron
(it has already been utilised by both plants and animals).

I'm have a question about chelated iron supplements, though-
if it is purchased from a garden or hydroponics store
it will likely be chelated with DPTA (Diethylenetriaminepentaacetate).
The makers of iron dietary supplements from the health food shop
seems to be a bit reluctant to list the actual chelating agent,
saying things like "amino acids"
(is DPTA not an amino acid?).

I'm wondering whether horticultural and human supplements
are actually the same thing
(gee, I can buy dietary supplements at Walmart garden centres!).
If they are not, how safe are the plant supplements for fish?
And for people who eat those fish?

Does anyone have firm information about this?
(guesses I can come up with myself!)