Dwarf Lobelia Melt Off. Anyone Grown This?

I split 2 pots of this to plant in my shrimpery, reading the label it should have been ok but I'm getting melt off in the smaller clumps with the larger clumps defoliating but making roots.

I've read that it can be grown without CO2 in good light but it struggles a bit in hard water. Has anyone else grown this plant successfully. I'm not giving up with it yet but it means I might need to rethink foreground planting in my shrimpery.

Shame, it's a lovely looking plant. 

I don't know what dwarf lobelia is (another case of English names not being clear). The only Lobelia I've seen as an aquarium offering is Lobelia cardinalis which isn't truly aquatic at all, I've grown it in my garden. Tropica give it as  a plant which requires intense light.

I'm sticking to the tried and trusted plants, so many can be a waste of time and money.

Yes, I agree, never gamble with fish, they are so difficult to roll around in the roulette wheel......
(health and safety notice:- never roll fish around a roulette wheel  )

As for all of this plant talk across several threads, I'm thoroughly enjoying it. As I've been setting up tanks over the past few months I've concentrated on the fish & axolotls, and have mainly used silk plants, with occasional patches of bunched plants just shoved into the sand. In the past couple of weeks I've noticed some of the bunch plants have rooted, grown and multiplied. As my 125L tank has been emptied of axolotls I have started trying to set it up as a planted tank for the tiger barbs, so the current discussion regarding substrates, plants, gas pockets, etc. have come at exactly the right time for me to learn as much as possible before finalising my set up. 
 

There are surprisingly few truly submerged aquatic plants. Most of them like to get their heads above water, so to speak, where they are much less restricted by light or carbon dioxide. Most of these plants are actually grown emergent rather than submerged, since they grow much faster that way.
It has been suggested that they are best slowly adapted by gradually raising the water level rather than submerging them completely immediately. After all, if a plant has been grown with only its roots in water and is then suddenly plunged to the bottom of a tank, it must be a bit of a shock.