Dwarf Rasboras Dying One By One

[508]

Hi all,
 
Got some Dwarf Rasboras that have been in the tank for maybe 6 months now. Nice little fish but I think my tank is not doing any good for them. I started out with 15, got 10 now, and they just seem to be acquiring more and more problems. One died in the night today, and he was incredibly skinny and I knew he wasn't going to make it long unfortunately, so it seemed like a growth problem. I also had one before who's spine seemed to grow sideways and I just noticed another fish is developing this as well. Noticed another one also seems to be growing weird, doesn't have the regular shape he should and spine is also kind of bent.
 
Should I be looking into rehoming? 
 
The PH of the tank is 8, hard water
Feeding them krill flakes, micro pellets, wafers, sometimes frozen
 

 

[Asteria]

I just had a look what they were and found some information for you 
 
'These fish are suggested for an intermediate aquarist. They are quite sensitive to their environment and any sudden changes in the water quality will weaken them significantly. They also don’t respond well to medications. If medicines are necessary, be sure to introduce them a little at a time by diluting the medicine with tank water before adding it.'
 
 

• Minimum Tank Size: 5 gal (19 L) - Due to its small size it can be kept in a five gallon tank, however the water quality must be diligently maintained.
• Suitable for Nano Tank: Yes
• Substrate Type: Any
• Lighting Needs: Low - subdued lighting - This fish doesn't like harsh lighting and will not show good coloration under such circumstances.
• Temperature: 74.0 to 79.0° F (23.3 to 26.1° C)
• Breeding Temperature: 79.0° F - Breeding temperatures need to be at the upper end of it's normal tank requirements.
• Range ph: 6.0-6.8
• Hardness Range: 1 - 12 dGH
• Brackish: No
• Water Movement: Moderate
• Water Region: All - They will swim in all regions of the tank.'

 
This is not my information. Nor am I claiming this is correct. 
But it seems your water may be too hard for these delicate fish

 

[Akasha72]

I also think the problem here is the water pH and hardness. Rasbora's are a soft water species and so with a pH of 8 and hard water they are not going to do well at all. 
 
It's always best to stock your tank with fish that prefer the water type you have 

 

[fluttermoth]

Do you know exactly what species you have, OP?

 

[Byron]

Yes, knowing the species would clarify, but if we assume this is one of the Boraras species like B. maculatus or B. brigittae, then the water parameters are most likely the issue.  These fish will be wild caught (unless you have a local breeder) and thus very demanding; and being so small (one of the smallest of freshwater fishes) their tolerance of parameters outside their preferred range is next to zero.
 
I don't know the source for the data cited by Asteria, but I would suggest that the GH should not be anywhere near as high as 12 dGH.  I would say no higher than 4 or 5 dGH (Seriously Fish has up to 90 ppm which is 5 dGH).  The pH as long as it is below 7 should not be a problem, but it can be much lower, 4.5 to 5 and up to 6 or so.  I have a group of B. brigittae in water with zero GH and the pH is at or below 5 (I don't have a test kit that measures below 5), and previously I had B. maculatus.
 
Diagnosing fish problems is not easy most of the time, and many different things can cause similar symptoms.  But here I think you are seeing what I would expect when soft water fish are maintained in harder water.  Over time the fish's physiology is working harder to maintain the internal homeostasis, and eventually it can no longer manage.  At this point the fish may just die with no external symptoms, or it may contract other issues which then seem to be the cause of the death, but it is the inappropriate water parameters that start this chain of events.
 
Please understand that I and others are not blaming you for this, it is something we all have to learn.  But fish are simply not as adaptable as some would have us believe.  Soft water fish rarely if ever live a full lifespan unless they have very soft and slightly acidic to acidic water.  It is likely that the increasing problems we are seeing in many of the "bread and butter" fish that were originally soft water and have over decades been supposedly "adapted" to harder water can be traced back to the parameters.  Fish just don't evolve that quickly.
 
Byron.

 

[508]

Thanks for the input everyone. I do understand everything that is said and agree with it, the hard water/high ph is most likely the cause of the issue, however now I am trying to think of the best course of action.
 
Rehoming them to a LFS won't really achieve anything, they'll just place them back in hard water and sell them to someone who 99% doesn't have a soft water set up.
 
And then if I put an advert up on Gumtree, I also doubt I'll be able to find someone suitable. Think perhaps I should just keep them for now? Not sure. 
 
I also have some Pygmy Cories, though they've been doing fine and shown no signs of ill health. Hope they are ok. In my last tank I had sterbais for over a year with none dying so perhaps they will be ok.
 
There is also a lack of micro fish that suited for hard water, which is mainly why I got these. 

 

[Akasha72]

hi again. There are some natural ways to soften the water that you could try. Bogwood can soften water so I would try adding some large-ish pieces of that. You can also soften it using peat but as I've never used it (my water is soft naturally from my tap) I'll leave someone else to explain how you do this
 
Your cories are also a soft water species and so I think finding ways to soften your water is probably your only option now. As you've said there are far more options with fish for soft water then there are hard water. You've not mentioned your tank size and so it's very difficult to advise you on hard water species.
 
Do you have a water test kit? The liquid drop testers are the best. It'll help us all to know your tank size and water parameters - pH, ammonia, nitrite, nitrate and gH and kH if you can. Also I'd test the tank and the tap for pH, gH and kH if you can, that way we know what we are dealing with. If you have a good lfs they will often test the water for you until you can arm yourself with your own kit. If you get your water tested at an lfs please do ask them to write down or tell you the actually figures. Many will say 'it's all fine' but not actually tell you what the numbers are. Unless we know the actual numbers we can't help you very much.
 
Hope that helps

 

[Asteria]

Adding on to Akashas softening of water in a natural way. Indian almond leaves are a big help with this.  
I to have hard water and am currently running a set up of soft water fish. The leaves and bog wood have helped me alot to have softer water. But it's still on the top end of hardness for my fish 

 

[508]

Not sure there is much of a point doing that honestly, I'd rather leave my tank PH stable to let the fish accumulate than to have it fluctuate as I've heard that's the real killer. Besides I don't want water that's tea-coloured, I don't have the right setup for it. It'd look wrong. 
 
My tank is 17 US gallons. Housing 6 pygmy cories, 10 dwarf rasboras and too many cherry shrimp to count. 
 
I can test for PH, but there isn't much point in testing for the others, I have cycled the tank and checked numerous times before that ammonia and nitrite were constantly at 0. I do about 40% water changes roughly every week so no problems there. I'll do the PH test later tonight to get the precise reading.

 

[Akasha72]

tea coloured water would only be for a short length of time until the wood stops leeching. Your fish will thank you for it as that is their natural habitat although I accept it's not for everyone.
 
It seems to me that you don't want to do what is best for the fish and so my advice would be to re-home your current stock and re-stock with fish that can live in the water you naturally have. Forcing fish to live outside of their natural needs is cruel and you are shortening their lives by doing so. 
 
I've just done a conversion for gallons to litres and it says your tank is around 64 litres. A tank of that size could house something like guppies which would love the hard water enviroment

 

[508]

I could try to put up an advert for them on Gumtree, but I doubt anyone who actually has a soft water set up will reply. Rehoming them to the LFS is pointless as they are most likely going to get sold to someone with the same set up so what's the point?

 

[Akasha72]

if you post your location there may be someone on here that will take them into their care happily

 

[508]

I'm in London. Will put up an ad later. Not going to bother with Gumtree, 99% of the people I've met on there are complete idiots. 

 

[Byron]

I'll offer a few comments on adjusting water parameters, first generally then getting to specifics.  While adding organic matter (wood, dry leaves, peat) can naturally soften and acidify the water in an aquarium, the extent to which this will work depends upon the initial parameters and the amount of organic material.  The higher the GH/KH, the less it will change, or conversely the more organic matter will be needed.  But adding this stuff on its own is not likely to make much difference unless you first dilute the water to lower the GH/KH.  You will note I am mentioning GH and KH in this; the pH is relative and will naturally follow, but without dealing with the GH/KH, the pH is not going to budge.  It may lower at first if chemical solutions are added, but will bounce right back up within 24 hours if the GH/KH are not dealt with.  This is because the mineral content of the water serves to buffer the pH; the KH is primarily responsible for this, but the GH is a part of the process.
 
It would help to know the GH and KH of the source water (tap water) in order to assess the situation.  This is easy to find out, or should be; if you track down the web site of the London water authority it should give the GH (general hardness or total hardness) and KH (carbonate hardness, sometimes called Alkalinity).  No need to buy test kits.  Once we have these numbers, it will be easy to predict this or that.
 
Diluting the source water with pure water, which can be rainwater (if otherwise safe), reverse osmosis (RO) or distilled, is the only way to safely reduce the initial GH/KH.  You have a relatively small aquarium involved, so this would not be too onerous.  Diluting the source water reduces the GH/KH proportionally; i.e., if the initial GH is say 15 dGH, reducing the volume by half with pure water will result in a GH around 7-8 dGH.  This is not going to change, meaning, increase, in the aquarium (unless you target it with calcareous substances), and will over time slowly lower.  Regular water changes obviously have to use softer water too, but again with so small a tank this is not involving gallons of water.
 
Once the GH/KH is dealt with, the pH will on its own naturally lower.  At this point, the natural biological processes that occur in all aquaria will also serve to slowly lower the pH.  The breakdown of organics (fish excrement, etc) in the substrate is the primary reason, along with fish and plant respiration.  All of these produce CO2, which produces carbonic acid, and the pH naturally lowers.  At this point, adding the wood and leaves will also have more of an impact on this, since the initial "buffer" has been significantly reduced.
 
We still need to know the initial GH/KH for the tap water in order to asses the situation.  You could end up with a very lovely aquarium for these fish, and it would be a source of inspiration and enjoyment for you.
 
Byron.