Oh What The Hell Is Wrong With My Tank?

[smudger72]

I have had so many problems with my brackish tank in the last month it's just not funny.

I went on holiday for a week and came back to find my 4 F8 puffers dead.The water quality was very very high in nitrate, no trace of ammonia very slight hint of nitrite.
Over the next couple of weeks I did lots of water changes, treated the tank for whitespot(lots of flicking from the remaining fishes) added melafix as my green chromide and orange chromides had nasty looking white marks on their sides.
All the chromides died over a period of a few days. They seemed fine looked healed were swimming normally and then quite literally were dead.
The only truely odd thing that I did notice is that all the fish that died would move into the current from the external filter and swim like mad. It was almost like they were running/swimming away from something, sounds silly I know.
I have just been given a Green Scat which has been fine for a week but this morning there it is swimming like mad in the current again.

Does anyone have any ideas as to what could be effecting my tank?
If this Scat goes the same way as the other poor fish then it's going to be curtains for this tank.....

 

[nmonks]

I went on holiday for a week and came back to find my 4 F8 puffers dead.The water quality was very very high in nitrate, no trace of ammonia very slight hint of nitrite.

Did you by any chance have someone feeding them? Almost without exception, it's best to leave fish for short periods (up to 7 days) without food. By all means turn the heater down to a minimum setting to slow down their metabolism, but even at regular temperatures fish can go long periods without food. Adding some Elodea or similar will give puffers something to graze -- most species eat some plant material and algae in the wild, and being almost entirely protein-free, plants don't cause water quality problems.

Over the next couple of weeks I did lots of water changes, treated the tank for whitespot (lots of flicking from the remaining fishes) added melafix as my green chromide and orange chromides had nasty looking white marks on their sides.

Repeat after me: Melafix is useless... Melafix is useless...

I know Melafix sometimes works, but it's so inconsistent as to be as good as useless. When treating puffers I use eSHa 2000 and eSHa EXIT, both of which seem 100% safe with puffers and are widely used in aquarium shops for treating delicate fish. It's worth mentioning though that you shouldn't (couldn't) have Whitespot in a brackish water tank. Whatever the problem was, it wasn't this. Even very low salinities (less than SG 1.001) are used to treat Whitespot on loaches and catfish.

I'd be more concerned about rapid changes in pH, which cause fish to "flick" as their gills get irritated. In brackish water tanks it is very common for pH to slowly decline over time, especially when the salinity is low. The problem is lack of carbonate hardness. Contrary to myth, simply putting calcareous sand or rocks in the tank has little to no effect. The calcareous media has to be in contact with water AND free of algae and bacteria. So in practical terms, we're talking about media bags in the filter filled with crushed coral, periodically cleaned/replaced as required.

The only truely odd thing that I did notice is that all the fish that died would move into the current from the external filter and swim like mad. It was almost like they were running/swimming away from something, sounds silly I know.

Not silly at all; in fact very perceptive. When fish are alarmed or stressed, their instinct is to swim away from the problem. It's the same as when cats get sick, they hide; not because they "crawl away to die" as people think, but because their response to fear and pain is to idea, and they can't distinguish the pain inside their bodies from pain inflicted by a predator. So your fish know something is wrong, and the best they can do is swim away from it.

Your list of things to do is this: No food for the fish. Check the filter. Check the temperature. Check the pH is where it should be (i.e., stable). Check the nitrite (to get a handle on water quality). Do a water change. Review sources of possible pollution or poison, e.g., dead animals in the tank, insecticide sprays, food past its sell-by date.

Hope this helps, Neale

 

[Colin_T]

When sick fish swim into currents it is often to help them breathe. If there is a water quality issue then they will often gasp at the surface or hang around an airstone or filter outlet. The moving water often has a higher oxygen level and this can help the fish.

I'm not sure about figure 8 puffers but many puffers are poisonous and release toxins into the water when stressed or dieing. This could have been a contributing factor to the problems in the tank.

When you do a water change, do you make the water up and use it straight away, or do you make it up and leave it for a day to mix & aerate? It is better for the fish if you allow the marine salt to dissolve properly in the freshwater before you add it to the tank, (24hours is sufficient). Also use a dechlorinator in the freshwater before adding the salt.

 

[nmonks]

I'm not sure about figure 8 puffers but many puffers are poisonous and release toxins into the water when stressed or dieing. This could have been a contributing factor to the problems in the tank.

Pufferfish lose their toxicity in aquaria very quickly (supposedly within weeks) because of the absence of dinoflagellates in their diet. In any case, so far as I'm aware, the "leak poisons into the water when stressed" thing where puffers are concerned is a myth. The poisons are in their tissues, unlike the situation with boxfish (Ostracion sp.) where poisons are in their mucous. Quite possibly there's been some mix up in the hobby between puffers and boxfish.

When you do a water change, do you make the water up and use it straight away, or do you make it up and leave it for a day to mix & aerate? It is better for the fish if you allow the marine salt to dissolve properly in the freshwater before you add it to the tank, (24hours is sufficient). Also use a dechlorinator in the freshwater before adding the salt.

Dechlorinator used properly should make your water safe to use at once. At brackish water salinities, you can mix the salt in and expect to use the water within twenty minutes. There's so little salt involved, and the fish used so tolerant of salinity changes, that slight variation doesn't matter. As for the "aerate for a day" practise, this made sense in the 50s and 60s when people didn't use dechlorinator. It's redundant nowadays. Just like activated carbon and tonic salt in freshwater tanks!

Cheers, Neale

 

[iSnail]

Sorry for your loss Hope your tank settles and fish get better soon.

 

[smudger72]

.

Your list of things to do is this: No food for the fish. Check the filter. Check the temperature. Check the pH is where it should be (i.e., stable). Check the nitrite (to get a handle on water quality). Do a water change. Review sources of possible pollution or poison, e.g., dead animals in the tank, insecticide sprays, food past its sell-by date.

Hope this helps, Neale
[/quote]


Neale,
Thanks for the reply, this is where I am today.
Filter seems fine just given it a clean, wasn't dirty though lol.
Temperature is pretty stable at 25 deg drops a couple overnight normally.
PH was just under 8 this morning, just tested it's at 8.
SG is 1.005
50 lt water change as normal done this morning.
No dead animals in the tank all 7 that died were removed.
No sprays are used near the tank, the wife knows better than that ;-)
Food is all within sell by date, I only buy a couple of packs of frozen at a time to make sure I don't keep it too long.


While on holiday someone did stop in and checked in on the fish for me, he found the puffers dead he removed 3 of them not realising I had 4, the fourth was found when I returned.
I reckon I can trust him as he is the owner of a lfs(rather good one as well) which is in the PFK top 20 shops.

The scat is still swimming in the current until I go near the tank and then it comes straight over for food lol. It does seem to have clamped fins though. The only time I see the dorsal fin exposed is when it feeds?


I really am at a loss to know what killed/is causing this strange behaviour in the tank.

 

[nmonks]

This all sounds fine. I'd be tempted to put the death of the puffers during your vacation down to "user error" of some sort. The aquarium sounds fine at the moment. Maintain normally, observe carefully.

Cheers, Neale

Filter seems fine just given it a clean, wasn't dirty though lol.
Temperature is pretty stable at 25 deg drops a couple overnight normally.
pH was just under 8 this morning, just tested it's at 8.
SG is 1.005
50 litre water change as normal done this morning.
No dead animals in the tank all 7 that died were removed.
No sprays are used near the tank, the wife knows better than that ;-)
Food is all within sell by date, I only buy a couple of packs of frozen at a time to make sure I don't keep it too long.

 

[smudger72]

It's started again.
Exactly like last time
One GSP dead it suddenly got cloudy eyes belly went back and was dead this morning (found ill wednesday).
Scat is swimming like mad in the current from the filter along with the mollies.
Knight gobies flicking on the sand.
PH stable @ 8
Ammonia 0
Nitrite 0
Nitrate 25mg

Water is cloudy?

I am just off to bash my head repeatidly against a brick wall.

 

[el_vulture619]

How old is this tank? Maybe it hasnt cycled properly yet.

From the way you describe the fish behavior I would say parasites. Maybe some gill parasites. You may also have some internal parasites. Try raising the temp of the tank, and no food for a week. If all the fish die off I would leave it empty for 6wks while doing regular water changes to let the parasites die off.

 

[Marine/Freshwater?]

Dechlorinator used properly should make your water safe to use at once. At brackish water salinities, you can mix the salt in and expect to use the water within twenty minutes. There's so little salt involved, and the fish used so tolerant of salinity changes, that slight variation doesn't matter. As for the "aerate for a day" practise, this made sense in the 50s and 60s when people didn't use dechlorinator. It's redundant nowadays. Just like activated carbon and tonic salt in freshwater tanks!

Cheers, Neale

What do you mean when you say activated carbon is redundant?

 

[smudger72]

How old is this tank? Maybe it hasnt cycled properly yet.

From the way you describe the fish behavior I would say parasites. Maybe some gill parasites. You may also have some internal parasites. Try raising the temp of the tank, and no food for a week. If all the fish die off I would leave it empty for 6wks while doing regular water changes to let the parasites die off.

The tank has been running since January, I had no problems until August when I lost my puffers and chromides.