Entire aquarium dead

[Morasea]

I ended up scaping a new, larger tank for some fish last Wednesday and then left town for the weekend on Friday. I came back today to everything i transferred into the new tank dead. I ended up transferring some substrate (Fluval stratum and sand), plants and my filter. I also added lots of new plants and driftwood. I’ve checked the usual problems like ammonia and nitrates and everything seems ok. It has a strange film or sludge on top and the entire tank smells. Does anyone have any idea where I could’ve went wrong? All these fish were doing great in their previous tank together.

The stocking was 20 chili rasboras, 10 Pygmy corydoras and 2 scarlet badis.

 

[Back in the fold]

Did you put something new in there without cleaning it ?

 

[Byron]

It was possibly the substrate, especially the Fluval Stratum. There is a host of various bacteria species that live in the substrate, and there can be "dead" spots which are fine until they are disturbed. Did you wash/rinse the substrate before using it in the new tank?

Another possible cause was something toxic leeching from the new wood. You mention a sludge (which is undoubtedly from the organics and stuff in the substrate) but is there any sort of whitish film on any of the wood? Do you know what type it is?

Unfortunately the fish species involved are quite delicate and highly susceptible to any of this, whatever it may be. Their small size is part of this, smaller fish have a higher metabolism.

 

[Morasea]

It was possibly the substrate, especially the Fluval Stratum. There is a host of various bacteria species that live in the substrate, and there can be "dead" spots which are fine until they are disturbed. Did you wash/rinse the substrate before using it in the new tank?

Another possible cause was something toxic leeching from the new wood. You mention a sludge (which is undoubtedly from the organics and stuff in the substrate) but is there any sort of whitish film on any of the wood? Do you know what type it is?

Unfortunately the fish species involved are quite delicate and highly susceptible to any of this, whatever it may be. Their small size is part of this, smaller fish have a higher metabolism.

After doing a little research I found that used Fluval stratum retains gas and the dead areas that you mentioned so I’d have to think it had to do with that. With that being said what would the course of action be? Maybe do large water changes?

 

[Morasea]

I also got the the driftwood from a dedicated aquarium store. I believe it’s manzanita.

 

[Byron]

If it were me, I would dump the Fluval Stratum out into the back garden. Use soft sand, the least expensive and frank one of the best being Quikrete Play Sand; I've used this for alost a decade now. Look for it in Home Depot or Lowe's, it comes in a basic natural buff tone, and in a dark grey. I prefer the latter, but either is ideal. Your pygmy cories will love it! Mine sure did, I had 30 fry growing up from 6 adults. The sand you have, if it is inert, may be OK--with cories one must be careful. I would buy a bag of QPS and be safe; rinse it, but the "dirt" is not problematical so don't go overboard!

The so-called plant substrates are more trouble than benefit. And, they should never be used for cories or loaches. Bacterial issues are very dangerous.

The wood is likely OK, it was just another possible. The surface "film" and smell was undoubtedly the substrate.

 

[Morasea]

If it were me, I would dump the Fluval Stratum out into the back garden. Use soft sand, the least expensive and frank one of the best being Quikrete Play Sand; I've used this for alost a decade now. Look for it in Home Depot or Lowe's, it comes in a basic natural buff tone, and in a dark grey. I prefer the latter, but either is ideal. Your pygmy cories will love it! Mine sure did, I had 30 fry growing up from 6 adults. The sand you have, if it is inert, may be OK--with cories one must be careful. I would buy a bag of QPS and be safe; rinse it, but the "dirt" is not problematical so don't go overboard!

The so-called plant substrates are more trouble than benefit. And, they should never be used for cories or loaches. Bacterial issues are very dangerous.

The wood is likely OK, it was just another possible. The surface "film" and smell was undoubtedly the substrate.

Thanks very much for the insight. Im just surprised the stratum was able to release enough bacteria in a couple days to kill the fish. I just want to put it out there that the sand has been capping the stratum the entire time I’ve had it and just making sure the bacteria is still likely the cause.

 

[Byron]

Thanks very much for the insight. Im just surprised the stratum was able to release enough bacteria in a couple days to kill the fish. I just want to put it out there that the sand has been capping the stratum the entire time I’ve had it and just making sure the bacteria is still likely the cause.

There is a thread from a couple months back where the member changed the substrate in her aquarium and hit a dead spot without realizing it. She had left the fish in the tank and sad to say, they all died within a day. Anaerobic spots such as under wood or rock are fine, and part of a healthy substrate, but not when they get disturbed. I've come across them frequently when changing out the substrate (and they certainly do smell foul!) but this is always with no fish or plants in the tank.

The added problem here is the Stratum itself. And capping it with sand is generally not good, as the sand will settle to the bottom leaving the stratum material on top, and you cold lose all the cories with a few days. Barbel degeneration in cories can be caused by a rough substrate, but more often it is bacteria in the substrate. This is worse with gravel compared with sand because of the grain size.

 

[Morasea]

There is a thread from a couple months back where the member changed the substrate in her aquarium and hit a dead spot without realizing it. She had left the fish in the tank and sad to say, they all died within a day. Anaerobic spots such as under wood or rock are fine, and part of a healthy substrate, but not when they get disturbed. I've come across them frequently when changing out the substrate (and they certainly do smell foul!) but this is always with no fish or plants in the tank.

The added problem here is the Stratum itself. And capping it with sand is generally not good, as the sand will settle to the bottom leaving the stratum material on top, and you cold lose all the cories with a few days. Barbel degeneration in cories can be caused by a rough substrate, but more often it is bacteria in the substrate. This is worse with gravel compared with sand because of the grain size.

Ok again thank you very much! The only thing left for me to know is if the filter needs to be changed out or the media inside

 

[Byron]

Ok again thank you very much! The only thing left for me to know is if the filter needs to be changed out or the media inside

That's a good question. Normally moving the filter over without "cleaning" it can ensure success avoiding any ammonia/nitrite issues. I'd be worried that the aerobic bacteria you want to keep by doing this could be lessened/killed. Whatever the answer to that may be, here theree are no fish left so you are cycling afresh anyway, so I would give the filter media a jolly good cleaning under the tap. I might even replace the media for added safety.

Do you have live plants? If yes, they will take up ammonia from the new fish and "cycling" is basically a non-issue provided the plants are thriving and there are some fast growers (floating plants are ideal for this).

 

[AdoraBelle Dearheart]

I'm really sorry to read about your tank loss, that's the most horrible thing to come home and find! That's awful, I'm so sorry


I'm a bit confused about the substrate thing, did you add any new substrate to the new tank, or transfer all of the substrate from the old tank?
Also, did you use a holiday feeder while you were gone, or have anyone else feed your fish? Not implying you should have! Most fish are usually fine to fast for a week or two. Just wanted to explore other avenues that could have contributed, like a feeder dumping out too much food at once.

 

[Morasea]

Thank you for the kind words .Right now the tank is heavily stocked with plants. I’ve got a mix of duckweed and dwarf water lettuce on top and too many others to name over the wood and in the substrate.

Basically what ended up happening is that I used half of a new bag I had lying around and the other half was stratum from the previous tank. While I didn’t take a huge amount of dirt I still probably would’ve taken enough to cause chaos. As for the feeding I believe my roommates fed them one night and there didn’t seem to be any leftover food so I don’t think that would have caused it

 

[Wills]

Great advice in here too but one other thing with the Stratum substrate - in the first few days of being in the water the new media would have leached ammonia for a few days, typically 1-2ppm on a liquid test but if you had a mature filter on there it could have processed this. Certainly if you had dead fish in there and still 0 ammonia when you tested the filter is dealing with the ammonia.

If you are adding new soil in (like Stratum) its best to do it in a new tank where no livestock will be added for few weeks. I have a slightly different opinion to Byron on it and I do think it has a place in the hobby but I agree not the best substrate for fish like Corys and Loaches. And when it comes to rescaping with soil and adding fish straight in, best to stick to what you have and add root tabs in the way you wound an inert substrate. I'm rescaping my tank this week and I'm going to move my soil into bags to go under sand which I have in my 8 gallon and has worked well.

Wills

 

[GaryE]

We're always trying to replicate nature, but we don't have ways of having the all important one direction flow of water to carry away the results of disturbed dead spots, etc.

 

[Byron]

You have some fast growing surface plants so you will not see "cycling" issues if you use all new sand. And I do recommend this, to avoid any carry-overs. Aquascape the tank, fill it with dechlorinated water, and when you're satisfied add the fish you intend housing. Always add the entire group of a shoaling species at the same time.

BTW, just for your information, there is no plant called "dwarf water lettuce," there is one species, Pistia stratiotes, and it will grow to "x" size solely determined by the environmental conditions. A few years back I had this plant in a couple of tanks and it attained around 3, 4 or 5 inches across. I also tossed a few in the outdoor pond in the summer, and they grew to 8 or 9 inches. Light and nutrients determine the growth. There were only a couple of goldfish in the pond, probably not providing sufficient nutrients to grow larger plants, as the light and CO2 would have been the max. I fed the fish but no plant additives went in the pond.