Danios Suffocating?

[squidsagirl420]

I suspect my danios are suffocating. lost three already. checked ammonia its .25 and nitrites are 0.
didnt change my water for a month when i usually do it every two weeks. 
did a water change today when i found the first dead and after, other danios started acting lethargic at the top and lost the two others.
so thats when i checked ammonia and nitrites. when i saw .25 i went ahead and did a large water change. and now just kinda watching the fish.
any idea what to do now? or whats wrong?

i have 9 tiger barbs that seem fine
2 ghost shrimp seem fine
and then 6 leopard danios left.
oh and one nitrite snail.

(none are full grown)
cycled 20gal cube
aquaclear 50gal filter

 

[wet44]

You shouldn't have ammonia in your cycled tank. Even that amount of ammonia is going to be really dangerous to your fish. I would also recommend testing your tap water and comparing it to your tank water as well.
 
You should start doing water changes and testing your parameters daily to minimize the amount of ammonia in your tank. I'm not the best at stocking levels, but that many fish seems like too many to me. Someone else would be better to confirm that. 
 
Definitely once everything is back to normal, it's going to be necessary to continue weekly water changes of 50% I'd say.
 
Hopefully your tank is back on track soon!

 

[squidsagirl420]

Well i had them all to 0 at one point, so i thought it was cycled. and i havent added any fish. but lost some ghost shrimp along the way. i never saw bodies because i had seen a tiger barb with an entire shrimp in his mouth. LOL so i assumed they ate them. i guess its possible that there is a body i havent seen? that caused ammonia? anyway, i have had this many fish for some time and as far is a was told, the filtration i had would be ok with that many as long as i water change enough. wooops. :\ oh summertime.

i actually only have 8 barbs not 9. and i lost another danio so im down to 5. makes me sad. everything was great for months. then i got lazy with water changes the past month. 

one of the male danios is remarking his territory after the big water change. maybe they will be ok.. ugh.

 

[Byron]

I just responded to your PM, but will comment here too, as there is more data in this thread.
 
I agree with wet44 that there are way too many fish in this 20g tank.  Now that I know that, the fact that you were unable to do regular water changes for a period caused the environment to become very dangerous.  Smaller more frequent water changes will likely be better than doing larger ones to get things more stable again.
 
I mentioned pH in my PM...I would suspect the pH has lowered below 7 and is thus acidic.  Changing too much of the water using tap water with likely a higher pH (above 7) will cause not only pH shock but any ammonia in the water which in an acidic pH is basically harmless will suddenly turn very toxic when the pH rises above 7.  Either or both the pH shock and ammonia is likely the issue with the danios gasping.
 
For the future: A 20g is really too small for most danios or barbs as these are active swimmers needing length.  On top of this, Tiger Barbs should be in no less than a 30g tank, on their own, as minimum.  So removing the remaining danios would be a good idea.  With more frequent maintenance (significant water changes) and live plants, one can sometimes "get by" with slightly over-populating an aquarium, but the risk is that should anything go wrong as it did here, the result can be the loss of the fish.  We all live and learn, hopefully.
 
Byron.

 

[squidsagirl420]

yes. makes sense because i did small water changes pretty often until this point. and all had been perfect. it is pretty planted but im not sure how planted its considered. after the large water change they did stop hovering at the top and seem a lot better but i guess only time will tell. i did loose three in the end which sucks. still curious if i have a lost dead shrimp somewhere... but the only other tanks i have is a 10 gal with a mystery snail. and then a tall skinny hex 30gal. that has a mini crayfish (about 1inch long) neither are probably good for the danios..

also, my dominate danio is a female and she chases them all around. i wonder if she stressed them too much on top of bad water. (and also must be some boredom if space is lacking) 

 

[squidsagirl420]

this was my reading, and a pic of my tank.

 

 

[Byron]

That looks nice.  Do you know what the pH is?

 

[squidsagirl420]

i will do a test real quick

 

[Munroco]

A 20 gal tank (17 UK), should comfortably hold 8 Tiger barbs and a few danios IMO. Looking at the pic it seems to be about 18" square?. Its about the same volume as a 36" long. As long as there is adequate filtration the oxygen levels should be fine. Ammonia is a different matter which I'll leave to others more knowledgable.

 

[squidsagirl420]

ok. here are my readings. and it looks my ph is crazy high at around 8.2
the regular test was so dark i also did the high range.
 

 
 
all are showing a tid bit darker on pic than actuality 
 
as far as the amount of fish. i honestly think it was fine, though i know thats not always going to be the case. i do have a good filter. but i also agree that i have more work on my hands in having an overstocked tank. also, the amount is only one matter, the other is type of fish, danios deff need more side to side swimming and i know they are irritated with not having long distance swim space. I have noticed it before. cant deny that.

what do i do now? thanks byron

 

[Byron]

A 20 gal tank (17 UK), should comfortably hold 8 Tiger barbs and a few danios IMO. Looking at the pic it seems to be about 18" square?. Its about the same volume as a 36" long. As long as there is adequate filtration the oxygen levels should be fine. Ammonia is a different matter which I'll leave to others more knowledgable.

 
It is important to recognize what this species (Puntigrus tetrazona, the Tiger Barb) requires, which is somewhat different from many others of comparable size.  The inherent aggressive nature means the fish needs numbers, with 8-10 being minimum.  The active swimming nature means length is much more important than volume.  This species prefers a habitat of forest streams rather than quiet waters, which tells us something.  Most sources will suggest a 30g tank that is 30 inches in length by 12 inches in width as absolute minimum for a group of 8-12 TB, with no other fish.  As soon as other species are added, particularly those occupying the same water level such as danio would, the tank size must increase.
 
When I am faced with offering advice in circumstances when the ideal or preferred is not going to be met because of existing situations, I try to suggest the best option.  Here, I would remove the danios as they are going to impact on the barbs no matter what, and then we are left with the 8 barbs in suitable water volume though not perhaps "best" in terms of the fish's expectations (thinking of the tank dimensions).  But having said that, I would expect the barbs to be reasonably "happy."
 
So back to my first sentence in this post...different species of similarly-sized fish would be a very different matter in this tank.  Figuring out stocking must take more into account than just the biological impact of the fish mass.  I hope this makes sense.  One site most members trust is Seriously Fish, and if you check their profile of this species it mentions a minimum tank with base dimensions of 80cm (30 inches) by 30 cm (12 inches) which is the 30 gallon--though no mention is made of height, but again, it is the length and width providing the horizontal swimming space that is critical to a species like this barb.  And by the way, I am a contributor to that site's knowledge base, though I did not author the subject profile, Matt Ford (the site's biologist owner) did.
 
Byron.

 

[squidsagirl420]

see i was thinking more about the danios because their obvious behavior. i didnt even consider the barbs wanting the same type of space. its interesting!  but they are pretty zippy when they want to be. so i could see how they would probably let loose in more space. or at least with less danios

do you think the danios would be ok in the tall hex though? with a mini crayfish? lol. eek

 

[Byron]

Squidsagirl, on the pH numbers...I suspect what I suggested in my PM occurred.  The absence of any water changes for a few weeks caused the organics to increase--and given the "overstocking" technically, this can be assumed probable.  The nitrate would likely have increased, and the pH likely fallen.  IF it fell below 7, the increase in ammonia which would also have occurred would not be noticeable in the fish's behaviour, since in acidic water ammonia is largely ammonium which is basically harmless.  As soon as you returned and did the major water change, using tap water with this higher pH, the tank pH almost certainly rose above 7, and the accumulated ammonium immediately changed into ammonia, which is highly toxic.  Thus, the danio began to succumb.  The barb is obviously a bit hardier fish and managed to get through this, though had I been present at the time I might have seen evidence of stress with these fish too.
 
Anyway, the water has stabilized now, the ammonia is minimal (many of us find the API 0-0.25 colours difficult), nitrite is zero, so the fish are able to "breathe easier" as it were.  Any idea about nitrate?
 
In answer to your final question in post #10, I believe I have suggested appropriate action for the future, but if any of that is not clear, please ask (in this thread so everyone is aware of what we are saying, I don't like hiding behind PM's 

 ).
 
Byron.

see i was thinking more about the danios because their obvious behavior. i didnt even consider the barbs wanting the same type of space. its interesting!  but they are pretty zippy when they want to be. so i could see how they would probably let loose in more space. or at least with less danios

do you think the danios would be ok in the tall hex though? with a mini crayfish? lol. eek

 
What volume and dimensions apply to the "tall hex"?  I personally would not mix fish with crayfish, though I know some do, but it is risky as the crayfish is very likely to consider fish something to grab and eat.

 

[squidsagirl420]

man, my poor fishies. i hate that it was my fault.
but you are now saying that things are as good as that are gonna get right now and to leave it alone right? lol

When would you recommend i do my next water change. and just small ones more often right? thanks again!
also, what did you think about the danios in the other tank? do i move them or will they just be more miserable

 

[Byron]

man, my poor fishies. i hate that it was my fault.
but you are now saying that things are as good as that are gonna get right now and to leave it alone right? lol

When would you recommend i do my next water change. and just small ones more often right? thanks again!
also, what did you think about the danios in the other tank? do i move them or will they just be more miserable

 
From the numbers, and your observation of the fish's improved behaviours, I would say you are probably over the issue and things should be back to "normal" for this tank.  Going forward, larger water changes will be better than smaller.  I'll explain.
 
When water changes occur regularly, meaning no less than once each week, it is generally much better to have larger rather than smaller volume changes.  This actually creates more stable conditions because it has more of an impact, and from week to week maintaining the same impact works to stabilize the biology.  For instance, a 10% water change every day will have almost no impact at all on most aquaria, whereas a 60-70% change once a week--which may seem to be the same, as 10% every day for seven days--is much more effective at maintaining good water quality.  And provided the parameters between tap and tank water are reasonably close, the fish will not be adversely affected but quite the opposite.  Even after doing 50-60% water changes in all my seven tanks for 15+ years now, it still amazes me how this stimulates the fish.
 
Jack Wattley, a recognized authority on discus, frequently writes in his monthly TFH column about water changes being essential to the health of the fish.  He notes that many discus breeders change 90% every day, and some several times a day--with the result that the fry develop healthier, faster and stronger.  You really can't change too much water, within reason and depending upon the specifics.
 
Byron.