The mysterious case of the melting frogbit

[hotweldfire]

2012-7-6_18.36.52 by hotweldfire, on Flickr

Please see pic above, especially the brown leaf on left side and snail moving in to take advantage.

This photo was taken at 1pm today. Lights go on at 2pm and off at 8pm. Frogbit went in at 6pm yesterday. Here's a photo tonight of a new plantlet that came off it when I pulled it out sitting in the smaller healthy tank it came from:


2012-7-6_19.6.43 by hotweldfire, on Flickr

In other words the plant was in perfect condition last night when it went in, had two hours of light and overnight started melting badly. Here's a pic of what Frogbit usually looks like in that tank.


2012-6-25_16.56.2 by hotweldfire, on Flickr

So clearly there's something not right with ferts in that tank but how the hell does a plant melt over night?

Ferts in the struggling main tank are EI, in the healthy small tank 6ml TPN and 6ml TPN+ a week in a 27l. Anyone know what the hell is going on?

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[hotweldfire]

Grrr. Bloody Tapatalk. Hang on and I'll get on a pc and sort those photos out.

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[darren636]

have they come from a humid environment- a lidded tank?

 

[hotweldfire]

Yep but both lidded tanks

 

[Matt Warner]

You could try taking the lids off and then see how it does?

 

[dw1305]

Hi all,
It might be lensing of condensation droplets, causing burn marks, but I think they've been eaten, look at the shape of the holes. If you look at the plant on the left side of the photo, on the larger leaf with 2 small holes, you can see the leaf mesophyll aerenchyma cells, (bit like expanded polystyrene) surrounding the small hole in the lower leaf surface. This is definitely damage to healthy leaf tissue. The snail? has eaten more of the protein containing chlorophyll cells in the palisade mesophyll from above, and left the structural carbohydrates of the aerenchyma.

I've just cut a cross section of a Frogbit Limnobium leaf to show what I mean.

I get this damage on spare plants in the pond etc, and I think it is terrestrial snails, but some snails are semi-amphibious like the Wandering snail (Physa fontinalis).

cheers Darrel

 

[hotweldfire]

Ok, thanks Darrel. That makes me feel slightly better as was getting very concerned about what was going on with my ferts. Unfortunately it renders frogbit as a fert index useless. You think the pond snails could be doing this sort of damage to other plants in my tank? Have holes in other plants but was assuming a CO2 or fert deficiency.

 

[dw1305]

Hi all,

You think the pond snails could be doing this sort of damage to other plants in my tank? Have holes in other plants but was assuming a CO2 or fert deficiency.

Yes, I think Pond snails (Lymnaea) eat almost everything. Ramshorns and MTS look pretty Limnobium safe, but I haven't kept any other snails (Tadpole, Apple etc) with it.

Unfortunately it renders frogbit as a fert index useless.

I've never had anything eat Pistia, Lemna or Salvinia as alternatives.

cheers Darrel

 

[hotweldfire]

You sure snails don't eat salvinia too (click to zoom, then click to zoom again)?


2012-8-16_20.22.57 by hotweldfire, on Flickr

BTW have a look at my anubias nana petite. Keep in mind this is growing under my mass of needle leaf java fern, i.e. pretty much in the dark, so it's nutrient/co2 needs should be minimal:


2012-8-16_20.22.36 by hotweldfire, on Flickr

So, pond snails? I've never had a problem with snails eating my plants before although I've always had pond snails. Assassins won't last long in my tanks because of the low PH so don't know what the solution is.

 

[dw1305]

Hi all,
The Anubias definitely looks like it has been eaten, which is a bit strange as nothing normally eats them. I've seen similar damage to Amazon Swords by hungry Bristle-nose (Ancistrus), but I still think it is snails. Have you tried baiting with a piece of courgette or similar? You should be able to thin the snail numbers out using this method.
I can't keep Assassin Snails either, presumably for the same reason.

I'm not sure about the Salvinia, it looks a bit like lack of light, but it may be that the snails have eaten into the mesophyll layer from below.

cheers Darrel

 

[Antipofish]

My frogbits gone the same way. Was getting better and better but now seems to have crashed