Plant Die-off

I have three tanks, a 125 litre, a 50 litre and a 25 litre. In the larger tanks I had a mixture of Salvinia (either natans or minima) and duck weed on the surface. The Salvinia in the 125 had been there since Jan 2010 and in the 50 since I got it last May. I've always had to throw handfuls in the compost bin to keep it under control. As for the duckweed, I did have some several years ago but it vanished, then it suddenly appeared again this year, possibly a contaminant in a bag of fish.

I did water changes on all my tanks this morning, slightly overdue (9 days since the last one) as I twisted my knee the day I should have done them. When I opened the tanks, I found all the Salvinia was brown in both tanks and all the duckweed was white. They were fine 9 days ago. I had noticed reddish speckles on the Salvinia in the 125 but assumed I'd accidentally tipped fish food over it when I was feeding the fish. The feeding hatch on the 50 is not over the end of the tank with the Salvinia so I wouldn't have seen anything in there.
The java fern and anubias look fine, it's just the floating plants that are dead.

I've tested the water in the 50 for everything I have testers for. It was only after I'd filled up the 125 that I realised I should have tetsted in there so did the 50 instead.

pH between 7.2 and 7.4
Ammonia 0
Nitrite 0
Nitrate 20 (tapwater 5)
KH 3
GH 8

All the test results look the same as they've always done.

Things I've done recently:
Added Seachem Flourish after the last but one water change (just over 2 weeks ago) at half the recommended dose as I don't have many plants, and from the same bottle I've been using for a year or so.
I bought some shrimps and fish 2 weeks ago, the fish went in the 125 and the shrimps in the 50. I did not quarantine them. I always net fish/shrimps out of the bag after acclimation so there would have been only a tiny amount of shop water got into each tank - and the shrimp tank at the shop was full of live, healthy looking duckweed.
I've fed the fish/shrimps finely chopped spinach over the last couple of weeks or so to try and give some green stuff to the cherry shrimps to see if that would help stop them dying (one website blamed the kind of deaths I've been seeing on lack of calcium containing food, and spinach contains calcium). I've put spinach in the 125 litre once (amano shrimps) but 3 or 4 times in the 50.




Help!!!!!!

What has killed my floating plants in two tanks at the same time? Why are the java fern and anubias still alive?

You really shouldn't be allowed to have plants! Duckweed is indestructible!  After the third Atomic Apocalypse, the only surviving species will be rats, cockroaches and duckweed. It's a criminal offence under the wildlife and countryside act to even let a sniff of this stuff escape into the wild. I think the penalty is the loss of your first-born 

The tirade above is cover for the fact that I don't know what has killed your plants!  Sorry. So I will have to make some suggestions.  9 days since your last water-change. (I hope your leg's better by the way) You have soft-water, so could you have had a pH crash? I assume the measurements you posted were from the 50 litre before a water change which would suggest not, but I don't know if the bioload on your other tank is significantly different. Nitrates at 20 isn't criminal (I would kill to get that level of nitrates in my tap water)

Seachem Flourish at half dose shouldn't cause any problems unless it was flourish excel, some plants are sensitive to this stuff. Similarly, I haven't heard of any lurgy you can introduce into a tank by not quarantining livestock that affects only floating plants!

Which leaves us with spinach! (As an aside, spinach isn't a desperately good source of dietary calcium. It contains a fair amount but it also contains other stuff that prevents it from being absorbed by the body efficiently, at least in people it does; I'm not sure if the same is true of fish.) This seems to have been the only significant change you have made recently so it must be suspicious. The only explanation that springs to mind is it could be caused by Allelopathic chemicals produced by the spinach.  I have never heard of such but...

PS. Sorry for the delay answering this but I had an eye-exam today and the drops they put in my eyes made them go "squiffy".  They have only just recovered.

Hey Steve, if you can still write Allelopathic then I think your eyes are fine!

As for the plants...... haven't a clue. Sorry.

The water parameters were pre-water change.
The bioload is similar in the two tanks - according to the CC they are 63% stocked in the 125 litre and 66% in the 50 (using real volumes of actual water not the manufacturers' volumes)
I didn't have a pH crash, that was the first test I did.
It was plain flourish, the one with trace elements. I don't use flourish excel very often as that made the leaves fall off the hornwort in the 50 litre (the only tank with hornwort). Though I gave up on the hornwort as leaves kept falling off anyway and making a mess on the sand, it was just a lot worse with flourish excel.

The website I found talking about failed moults and lack of calcium in the shrimp's food recommended kale. I don't know what I'd do with a whole pack of kale, it would last several years at the amount I feed them. But I do have frozen chopped spinach in the freezer. I scraped some off the side of a block. I'll stop using it just in case it was that (and it stops the shrimps absorbing calcium)
Any suggestions for calcium rich food suitable for shrimps? Do they make pellets for shrimps that contain calcium?


I did manage to find a few plants of salvinia that were still green. They are now in a tub of dechlorinated water on the windowsill, there's enough to cover maybe 2 square inches. Everything else was brown.



I've had duckweed die off before, I put it down to my aquatic plant growing skills. But it's the first salvinia problem I've had, and the java fern & anubias are still OK. And my african violets look wonderful now they are in flower 

Have we had any very hot weather since Jan 2010 until this last few weeks? Maybe Gaynor is right.....





My knee is fine now. I had knelt on the floor to sort out a drawer and got up awkwardly.

I know what you mean about eye exams, Steve. I was diagnosed with intraoccular hypertension (not glaucoma yet as my sight isn't damaged) earlier this year and with check-ups for that and screening for diabetic retinopathy I regularly have drops in my eyes. It looks as though someone has smeared your glasses with vaseline for several hours. I can see I have fish, but can't tell if they have fins 

You can get specialist shrimp food; One assumes that it contains calcium if shrimps require it, you would have to look at the label to be sure. The biggest problem would be delivery; how do you ensure that the shrimps get the shrimp food before the ravenous hordes descend?

My test was for diabetic retinopathy, it wasn't so much that everything was blurred, although it was, but that everything was so bright it hurt, even my screen!

I've just bought some Hikari Shrimp Cuisine on ebay - it's impossible to find specialist food locally. I'll feed that instead of spinach from now on. Hopefully it will help with the shrimps (it says it contains minerals to help with successful ecdysis) and not kill any more plants.

On a different note  (I know it was a separate post – sorry Steve!)

No apology required; I'm sorry, but I think I'm a little puzzled by this. The only thing I can come up with is the couple of posts I have made about off-topic or chained posts. If so let me stress to everyone, I have no intention of becoming the off-topic police. You may post what you like where you like. On the other hand, I reserve my right to comment if I think it may be better discussed elsewhere.

On a different note  you say

This summer so far is warmer than of recent.

Now I'm not disputing the cause of the problem is as you suggest; God knows, you know more about this stuff than I do, but I have to say that my summer has been far from "warmer than of recent". Quite the opposite in fact!

Thank you for your post Natalia, hopefully your plant problems will be gone now Sue! I was up in Durham at the weekend actually and it was really hot on the Friday - not at all how I remember my times up North at Uni!

 It is nice to see your posts here so do please keep popping back! I could do with some plant advice but I think I really need to look more into the actual plants I have and how to look after them properly! My java fern is looking a little rough around the edges, and the 'forked' version of java fern isn't looking too good recently except it has what seems like lots of roots growing out of the leaves - is that normal!?

If the treatment Beta G won't do any harm to my shrimp / fish if there is no problem I think I might as well get some and try it too! I don't want to lose any more shrimp, they are already a little thin on my ground at 4 now :-( I'm reluctant to buy any more until I've not lost any shrimp for a while. Will have a read up on it and source some :-)

I hope it's the right stuff because that's what I've bought. I'm just waiting for it to arrive. Bought it yesterday so in theory I should have had it today. Maybe tomorrow.

Ooh that's good then at least that's a somewhat positive sign that my poor plants aren't doing too badly!

Where did you order your beta-g from Sue? I've not ordered any fishy related things from anywhere other than Amazon before so wasn't sure if you had a reputable online source for yours as I'm always slightly sceptical about these things!