Is it normal that new plants discard leaves? / Is it necessary to remove rock wool?
Is it correct that plants discard their leaves after the purchase and grow new ones?
this is indeed rather common. Quite a number of plants is grown emersed in the nurseries, i.e. with their leaves in the air (only the roots are in the water in this case). When switching to submersed (entirely under water) life, these plants discard their leaves and grow new ones. Do not throw away such plants, this is normal! Even some species that permanently live under water sometimes discard their leaves. However, this is much less common and takes place mainly if the water conditions considerably differ from the previous ones.
Do I really need at least 15 plants in my 112 liter aquarium?
The general rule, almost without exceptions, is: The more, the better, provided there is sufficient swimming space left for the fish. 15 plants in the aquarium can be quite a lot (e.g. if they are medium sized to large Echinodorus swordplants), but also very little (e.g. if they are Ludwigia stems or the like), the question can therefore not be answered precisely without knowing the species in question.
Do I have to remove the wool of a newly purchased potted plant, or can I leave it where it is?
The rock wool should be removed as completely as possible, a pair of tweezers may provide good help.
Dr. Bodo Schnell