I planted 8 mangroves in my tank back in feb or so, and in about 6 cases there was complete defoliage, which did come back with time and a new light. In the last two cases the entire stem broke off; with these, one has produced three new stem heads with two leaves each, and have dropped nice red tap roots down, the last one hasn't produced any stems or heads, but has produced the largest tap root out of all of the mangroves including the most healthy ones! Just yesterday upon closer inspection there are three or four little red buds sticking out of the side, and it looks like they are going to explode out soon! So, it may be uncommon, but there is certaintly HOPE! I would just get a nice light on it, and make sure theres some nutrients in the water!
The large root in the foreground is the tap root from the headless seedling!
Here they are when they were in bad shape soon after I got them, shortly after this pics was taken, all of them completely defoliated, and some even whithered up there entire stem... (I was new to mangroves, and may not have acclimated them properly.... even though, I followed all directions and suggestions on this forum)
Either way, they look great now! and I am expecting a complete recovery from the last "headless" seedling! So dont give up, and it will hopefully sprout again!