As I understand things, very little beneficial bacteria actually live in the water. It is mostly in the filter, substrate, tank glass and decorations, so if you are keeping all those things I wouldn't imagine there would be too much of a problem.

Tetras can be nippy. Are you sure there is nothing sharp or rough in the tank that he can catch his fins on?

 

From what I know from looking at Congo tetra as I nearly got some myself, gorgeous fish, isthat they like a minimum group size of 5/6, preferably more, and a minimum tank size of 4ft. That's 48 inches and on average a 55g gallon. This is probably why your betta looks ragged. Fish kept in tiny unsuitable spaces can amongst many other things, become aggressive. Your congos will reach around 3 to 3.5 inches, and whether or not you class them as "small" now is not quite the point unfortunately. Fish need to be housed from the start in a size of tank that will suit them as full grown to prevent problems with the formation of their skeleton and internals, and shyness/ or in your case, presumed aggression.
Congos are a really active tetra and need a tank size that fits with this.


As for the size of the water change. Well. I'd say no, smaller is better. The reason we do smaller water changes is that over time in an aquarium which is an enclosed environment, the Kh and ph of the tank lowers, and so by doing massive whole tank water changes you can actually cause th fish distress by suddenly and massively changing their environment. Just my newish opinion, others MIght know better.

 

Larger water changes are fine if your source water is near to your tank parameters. Stabilize the temperature and treat as if you were adding the fish in for the first time. The farther the source parameters the more of a shock it may be to the fish the slower the process should be executed.

The following is not from experience and not intended as an inflammatory response, very little of this is my opinion, it's just working the facts as they appear. Take it as you will.

I don't think there is such a breed as a "small" congo tetra so you have the standard congo tetra which needs far more room than you have. A good guide when it comes to getting numbers of fish is to overshoot the stocking quantity as it not only ensures that the fish type have "enough" to behave as normal as they might in their environment but it allows for possible losses and overcompensating for the shoaling instinct. For me, (this is my opinion part), a recommendation of 6 or more means 12 or more as this will tend to keep fish tendencies (aggression, nipping etc) within the group.

Another good plan is to size the tank according to the largest size that the fish may get right from the start as well as to accommodate the expected quantity of fish. In this case the minimum suggestion is a 48" tank and 10 or more would indicate a tank of 35 gallons minimum, which isn't a 48" tank either.

From Aqadvisor.com... which can be a good place to start.

Warning: Congo Tetra is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 3 inches.
Warning: Congo Tetra will likely to fin nip Betta [Male].
Note: Betta [Male] may jump - lids are recommended. They can become stressful under presence of too many shoaling species. Try to keep under 1 shoal if the tank is small. Individual bettas may exhibit varying degrees of aggression and care should be taken that exceptionally aggressive/territorial fish be separated from a community before any damage may occur.
Warning: Betta [Male] is not recommended to be with Congo Tetra - further research is highly recommended.

Jeff.

 

Okay, thanks.

Well the reason I went with them in the first place was after reading here and having them recommended from a couple of people here as being alright to house together.

They were introduced at the same time and have been living together for a few months now, with no signs of any bullying/nipping until this week.

I have not seen the tetras harrassing the betta, at any time, in fact they seem to hang out at opposite sides of the tank (betta likes to swim around his hollow log) the tetras prefer to be around a group of plants on the other side.

I thought perhaps it was because of the water going longer between changes than they are used to. It's not his long fins that are ragged, its his pectoral fins. I can't see him swimming up against anything that would tear them. The plants are plastic but have been there from the start so I am sure would have shown signs of fin damage in the beginning if that were the issue surely?

The only 'picking on' that I have observed is the biggest tetra occasionally chasing the others, but they all do this to each other to some degree and it appears to be playful rather than aggressive? eg just chasing no biting

Does this mean I need to get rid of the tetras? I thought I had read up about them to make the best choice, obviously not.

Am worried if I remove the tetras that the betta will feel the tank is too big (if that makes sense) he is used to having tank mates. What else would work? No pygmy cories here or any shrimp that are ok with bettas.

As for the water, normally I only change about 20% but as I said, they really managed to mess up their tank so it was the only way to get all the particles out and give the filter a break.

 

Okay, thanks.

Well the reason I went with them in the first place was after reading here and having them recommended from a couple of people here as being alright to house together.

I can't speak to that.

They were introduced at the same time and have been living together for a few months now, with no signs of any bullying/nipping until this week.

I have not seen the tetras harrassing the betta, at any time, in fact they seem to hang out at opposite sides of the tank (betta likes to swim around his hollow log) the tetras prefer to be around a group of plants on the other side.

I thought perhaps it was because of the water going longer between changes than they are used to. It's not his long fins that are ragged, its his pectoral fins. I can't see him swimming up against anything that would tear them. The plants are plastic but have been there from the start so I am sure would have shown signs of fin damage in the beginning if that were the issue surely?

The only 'picking on' that I have observed is the biggest tetra occasionally chasing the others, but they all do this to each other to some degree and it appears to be playful rather than aggressive? eg just chasing no biting

Does this mean I need to get rid of the tetras? I thought I had read up about them to make the best choice, obviously not.

Am worried if I remove the tetras that the betta will feel the tank is too big (if that makes sense) he is used to having tank mates. What else would work? No pygmy cories here or any shrimp that are ok with bettas.

As for the water, normally I only change about 20% but as I said, they really managed to mess up their tank so it was the only way to get all the particles out and give the filter a break.

It very likely could be that the water issue stressed everyone out... or it could be that the "small" congos are coming into their own as they grow and mature. I'd be concerned that the Tetras will be too much for the Betta, they are certainly too much for the small tank. The chasing that you see now is usually spread out amongst the same species when there are enough. With too few in a small space they will end up picking on anything.

When I set up our new tank, a 37 gallon unit, our solo Betta was fine. In fact the extra space is not detrimental to the Betta, it's only our impression of too much space. He zoomed around checking everything out and ended up picking some resting places that surprised us.... 8 gallons for one Betta is certainly not excessive. Now he has 12 tank mates and all appears fine, but we are watching them closely.

Do you need to get rid of the Tetras? I would suggest doing so.

Adding other fish, I think the tank is too small to add anything that shoals, you can't add enough to make them work. Some tiger snails would, and they would help keep things neat too. I don't know about shrimp, I think that they would get eaten.

Jeff.

 

IMO I'd take them out. They far exceed th size limitations of your tank.

And as for the betta alone, I dont know much for temperament, but in a lot of cases - reponsible people wise - gone are the day when people keep them in 3 gallon 'jugs' and a lot of people nowadays keep them in 5 or 10 gallon tanks alone. He would probably love having the room all to himself!

 

My response will repeat what has largely been said, but sometimes we need to hear it often particularly if it is something we don't really want to hear.;-)

First on the water changes, this can be dangerous. As someone mentioned, the parameters are important. This involves GH, pH, and TDS (total dissolved solids). Most of us don't bother measuring the TDS as it takes some fancy equipment. GH is part of TDS but other substances add to them as well. When a tank receives regular water changes, at whatever level, the GH and TDS and the pH will remain basically stable. If water changes are lessened, the pH may drop, and TDS may increase. This will be relatively gradual, and the fish adjust accordingly. But performing a massive water change can adjust these parameters to such a degree that they shock the fish, and this can cause permanent internal damage which cannot be seen until down the road the fish develops disease or dies. So after a period of deteriorating water conditions, it is best to do smaller more frequent changes to restore normal values.

One thing with the pH. If it drops below 7, ammonia changes to ammonium which is harmless. If the water change then raises the tank's pH above 7, the ammonium changes back to toxic ammonia and fast. The fish cannot adjust to this.

As for water changes in general, provided parameters and other factors are relatively the same between the tank water and the source water, the larger the volume changed and the more often, the better. Just make sure it continues regularly.

To the fish problem. Betta should never, absolutely never, be combined with characins. Characins have lots of teeth, and they like using them. And they can be remarkably sly about it. I have sat motionless in front of my tanks for an hour or more, and witnessed some amazing behaviour from certain fish. Congo with their flowing fins are often on the receiving end of fin nipping, but they are characins and the presence of a Betta is like a red flag to a bull.

There is also the issue of tank space here being inadequate for this species (Congo Tetra). They need a 4-foot tank, no alternatives. They attain 4 inches (if they have space to grow properly), and they are very active swimmers. This is another issue with Betta; Betta, like all anabantids, are sedate fish and should never be combined with active fish for that reason alone.

The Congo being in close quarters are more likely to resort to aggressive behaviours like fin nipping because of the frustration they feel; they have no other way to deal with this except "lashing out," although sometimes fish in such situations do the opposite, they become withdrawn and slowly weaken and die. They must have sufficient space to be themselves. Nature has evolved each species to a very specific set of factors, and we cannot change this.

Byron.

 

Okay, thanks for the info. Feel bad coz I thought I did my research before buying but was obviously looking int he wrong places.

Will see if the place I got them from can take them back. They are a pretty big fish place so should be able to no hassles.

 

I'm going to cut against the grain slightly. Although 'normally' it's best to only do modest water changes so there is a gradual change in water chemistry, in some cases (like yours sounds) where a tank has run a muck, a tear down is required.

In that case, you merely need to preserve the beneficial bacteria integrity of the filter media and substrate and after the tank is put back together with fresh water of the appropriate temperature, use a slow drip acclimation so the fish slowly adjust to the new fresh water.

 

Let me see if I got this right.

You have tetras and a betta in and 8g tank and it's cloudy.

There is a highly technical term describing that condition.

It's called:




















Drum roll please.






























normal :lol:

As other have stated the tetras will nip at the fins of the tetra plus not have enough space or fellow tetras to establish a pecking order. Especially if you have less then 5 tetras which I hope so in an 8g. If you only have two or three they probably will not do well with the larger picking on the weaker. then during breaks nipping at the tetra.

Only solution IMHO is to remove the tetras and put them in a larger aquarium.

I also highly recommend planted tanks to prevent the cloudiness.

(FWIW: The cloudiness itself is IMHO nitrate and (mostly) phosphates plus carbon dioxide reacting to light forming the cloudiness. Killing the lights and suspendiing feeding will clear the tank. Then resuming with less lights and feeding and adjusting so the tank stays clear but plants still thrive.)


I definately would not change 100% of the water under any conditions. But then I never change any water under any conditions as well. It is best for the tank to basically "heal" itself then be reset to the initial start up values with a heavy bioload.

still just my .02
But then it is best to get the plants (added if not there already) and thriving (if there already).