Just to make sure that you know that this is Salvinia Minima not frogbit. Frogbit looks like min lily pads, while Salvinia Minima also known as fairy fern has harry leaves. But to answers your question they grow to about 1/2", they will grow very fast with C02 and ferts. too were you may need to thin weekly. They are very easy to thin since they grow in small clumps.How fast/big do the frog bite grow do you know?
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