The Puffer Forum

(I'm reposting this from fishforums.co.uk with some additional info)

Help! I've recently set up a small 70 litre (15 gallon) tank with the intention of transforming it into a low-end brackish tank for a Figure 8 Puffer and a few tankmates.

I bought an F8 from Wholesale Tropicals in London and introduced it to the fully cycled tank (fishless cycle, readings before and after the deaths were constant at ammonia: 0, nitrate 5, nitrite 0.1, pH 7.0). I also gave it some friends - three bumblebee gobies and a knight goby. The tank is a Juwel Rekord 70 with a sandy substrate and reasonably well planted with java moss, java fern, crinum calmistratum and something else I can't recall off the top of my head. There are three rocks in there, but no backing.

The F8 survived a week. So I bought another one. That survived 10 days. The gobies all seem absolutely fine but the F8s just seem to be dying, and I'm not sure why. With the second one we started moving the tank towards brackish shortly after getting it - we had done too 20% water changes introducing dissolved salts slowly each time, such that the tank is now up to an SG of 1.002 (aiming for SG of 1.005).

I was feeding them once a day in the evenings - the first guy had a mussel every couple of days and bloodworms daily, which the gobies helped him with. We also had some amano shrimps in there with him for about 4 days before they all died in the heat or through being snacked upon. The second guy pretty much the same but without the shrimps.

Possible explanations I was considering are:

• Before both of them died, I put a frozen mussel into the tank and left it there for about 48 hours. Could the rotting mussel flesh have poisoned it? But if so, why not the much smaller gobies?
• It could be a diseased batch, but Wholesale Tropicals has a good reputation and their own tank seemed to be doing okay. Plus I couldn't see any outward signs of disease.
• The tank could be too small for the F8. The second one seemed to spend all its time looking out, though the first one seemed to enjoy exploring the plants and rock
• They weren't eating properly. As well as the odd frozen mussel I was feeding them refrigerated live bloodworm, which they were eating, but they didn't seem to be very clever at finding food generally.
• It could be too hot. Our apartment has been sweltering in the summer heat and both this tank and our main tank (a 450 liter job) have been topping out at 29 degrees C during the day. But again, all the other fish in both tanks seem fine.
• They might be doing it to spite me.

Any thoughts on what the most likely scenario is, and whether there's anything else I should be doing if I want to keep these fish? Or is the tank fundamentally unsuitable for them? Or do I just suck as a puffer keeper?

Any help appreciated!

Tristan

the nitrite reading is a little high... that could be because of the uneaten food. If there are not consuming it all in in a few mins while under your watch it could be polluting your water. You MUST remove ALL uneaten food within 5 mins.


When you mention temps 29 C seems to a tad high.. are you adding extra oxygen to the tank via increased flow or an air stone? O2 levels drop in warmer temps.

What was the behavior BEFORE they passed on?

Hello Tristan, welcome to TPF
seems like a combination of things:
a tank is not cycled w/nitrites present
overstocked (very little water volume, don't know how much substrate you have or how big the rocks are, but their combined volume subtracted from the total 15 gallons leave very little)
over heated (and probably under-oxygenated as J-P said)
puffers are less tolerant of these conditions than most other fish
i doubt they're doing it to spite you!

A couple of theories:
1. You don't say what you cycled the tank with? Someone told me that to fishless cycle you just had to run your tank for about a month with nothing in it but that was incorrect and it turned out that you had to add an ammonia source regularly, needless to say the puffer I added died within two weeks of purchase but the bumblebee gobies are still going strong 4 years on! So from that you can see that gobies are much more hardy fish than puffers, this will most likely be due to the puffers lack of scales.

2. Lack of oxygen/overfeeding? The higher the temperature the less oxygen will be present in the water. When puffers gorge they can struggle to take in as much oxygen as normal. The combination of the two could have led to asphyxiation

3. Minicycle? You're tank could have been cycled but the addition of so many fish at one time (Puffer, Knight Goby and BBG's) could have been too much for the bacteria present and the tank went through a minicycle causing ammonia and nitrite to build up again and hence kill the most susceptible species in the tank.

The tank would have been overstocked with 2 figure 8's, Knight Goby and BBG's but even though an overcrowded tank can reduce lifespan it would not have led to deaths so soon.

goldbug wrote: I bought an F8 from Wholesale Tropicals in London

I have been to this fish shop on Bethnal Green RD so you must be local to me , anyway when I went there I saw the batches of GSPs and F8s they had in stock, they seemed healthy enough to me. Although one or two were sitting on the bottom! Whenever you buy a fish always be sure its eating before you buy it, never be scared ask to the fish guy to feed him for you so you can see he is eating!

That said I think the fishes deaths are your fault as having your tank at 29C will almost certainly cook them alive! So that why they died, if you are having heating problems in your room / flat. Then just turn the tank heater off and leave your room to warm the tank instead. Also putting a fan on top of the tank can help cool the water. Do you have Halides hanging over the tank, what lighting is there?

Walrus Head wrote:

goldbug wrote: That said I think the fishes deaths are your fault as having your tank at 29C will almost certainly cook them alive! So that why they died, if you are having heating problems in your room / flat. Then just turn the tank heater off and leave your room to warm the tank instead. Also putting a fan on top of the tank can help cool the water. Do you have Halides hanging over the tank, what lighting is there?

I don't think that this alone is the problem. I've run tanks at temps as high as 86 degrees during the summer - my parents don't run the A/C too often, and when they do, it doesn't travel through the vents to my room (old house). The temperature could have contributed, though. When my tanks are that hot, I feed slightly more (metabolisms speed up at high temps), and I always have lots of aeration and live plants to keep oxygen levels up.

ETA: 29* C = 84* F

Hi all - thanks so much for your responses!

A few comments:

• Whatever the actual nitrite reading is, the test results are the lowest option on the scale. Perhaps it means <0.1.
• Overstocking doesn't feel so likely as we only had one F8 in at a time. Both the F8s were still youngish - probably about 2/3rds grown I'd guess? - and same for the knight and bumblebees.
• I think an airstone might be a good idea in both my tanks, as I have been worried about oxygenation levels for a while.
• We cycled the tank for about 4 weeks before adding any fish to it, and we did it using the plant substrate (I don't remember the brand) as an ammonia source. I tested regularly to see how ammonia / nitrate / nitrite levels were doing and they spiked at first then slowly came down. Of course, when we added fish we added them with Cycle. I don't think it could have been a minicycle either as the ammonia levels were still zero straight after puffer #1 died.

So my main conclusion I guess would be overfeeding. I was chucking in a good two tablespoons of live bloodworms (in water), but I did notice that some of them managed to burrow their way into the sand which means they weren't being snaffled. The mussels were the main concern though and I think it highly coincidental that they both died after I'd left half an uneaten mussel in the tank for a couple of days. The only thing is, I would have thought the way this would manifest itself would be an ammonia spike, but readings still indicated zero. Nonetheless, I'm going to assume this was the problem.

If I get a third F8 - third time lucky?! - what do you think is the best way to feed him? My girlfriend suggested maybe holding the frozen mussel with tweezers but the puffers we've had so far were very shy.

What else could I do to ensure its health? I really don't want to be bringing wild-caught puffers into my home to die - it seems very unfair - yet at the same time we really want to have one and give it a nice home and a long life. We're just a bit inept at doing so at the moment!

Tristan

Overstocking actually is quite possible. Each F8 requires at least 15g, with additional water for tankmates.

Cycle is a pretty useless product - dead bacteria.

My advice is to leave it for another month or so to allow the tank to become more mature and established since it is clearly having problems at the moment.

I'm assuming that you're using a dechlorinator when changing the water?

As for feeding - just buy a net. Drop the food in, leave it for a while until you think that they've had enough and net it out.

I suggest reading the cycling articles in our library. It sounds to me that the tank was not cycled properly. The tank is also overstocked. Read the Profile on F8s in our Pufferpedia.

Hi all,

Thanks again for the advice. Pufferpunk, I've read the article on fishless cycling and I'm not sure how else I should have cycled the tank? I used an ammonia source (the plant substrate) and bacteria source (Cycle and the filter sponge), waited until ammonia / nitrate / nitrite readings were all bottomed out, then waited another week before adding fish. Ammonia / nitrate / nitrite readings stayed at zero, even after one of them died!

As for overstocking: both F8s I've had were on the small side (about 4cm), and the gobies are also all immature. Two of the bumblebees are tiny and the Knight is maybe 2/3rds grown. Do we really think the tank was overstocked at this stage?

The gobies all continue to do well on a diet of bloodworms though I am still concerned that they're not getting everything I put in the tank. I might invest in a worm feeder. From everything I've read on this forum and others, it really feels like the problem with the puffers was overfeeding.

I guess I have a decision to make about whether to try again and risk killing another F8. What would others recommend?

The tank is just too small for a f8 . And when you are adding tankmates you are massively overstocked! Please bear in mind that substrate etc will take away from your total volume. If you wish to keep a f8 please buy a bigger tank around 20g minimum for just him or much bigger if you want tankmates.

Hi bertie - you think so? I guess I hadn't taken into account that the substrate, rocks, plants etc are shrinking the amount of water substantially.

Just so I understand though, do you think this could have killed him? I just think back to the shop I bought them from where there were about a dozen of them in an even smaller tank! And they seem to be doing okay. . . !

Tristan

goldbug wrote: Just so I understand though, do you think this could have killed him? I just think back to the shop I bought them from where there were about a dozen of them in an even smaller tank! And they seem to be doing okay. . . !
Tristan

Don't judge species requirements by what you see at the LFS, they are holding tanks only and some have combined filter systems. Also go to most LFS's early in the morning and they will be netting out dead fish.

A 15(US)G tank is currently the minimum size tank recommended by The Puffer Forum for a single F8 so you were overstocked when you added the other fish but to suggest that this killed him in under a couple of weeks is bordering on absurd, it would have shortened his lifespan, yes, but not so soon.

You have to look at the nitrogen cycle in your tank to understand what is 'probably' the cause. Put into simple terms you need bacteria to convert ammonia to nitrite and another type of bacteria to convert nitrite into nitrate. the bacteria colony builds up depending on how much ammonia and nitrite is available to them, i.e. less ammonia = less bacteria. It sounds like your bacteria colony was overwhelmed by the bio-load of the fish and rotting food that were placed into the tank because your plant substrate did not leach enough ammonia into the water column. In short your tank wasn't cycled adequately for the bio-load.

I note that you waited a week after the ammonia level reached zero before introducing the fish. If the tank no longer has an ammonia source then the bacteria begins to die - plant substrates do leach ammonia when they are first introduced but that eventually settles down and the traces that are leached are negligible - A planted substrate manufacturer would soon go out of business if the level of ammonia it produced was as high as the combined bio-load of Figure 8 puffer, Knight Gobie and 3 BBG's!

Thanks Iliveinazoo!

Yes, I'm certainly not advocating keeping a dozen puffers in my tank, don't worry. . . ! And I've seen plenty of dead fish in these shops, at all times of day, to know they are far from ideal environments.

Also I didn't realise that 15 gallons was 15 US gallons. In which case I have an 18G tank all in, as it is 70 litres.

I totally get what you are saying about the nitrogen cycle - but what I don't understand is, if this was the problem, why were my ammonia / nitrate / nitrite readings still 0 the day he (the first one) died? Could it be that in the week he was introduced, the ammonia levels rose, poisoning him, but dropped again in the time it took him to die?

Tristan