# Overstocked?



## Evil-Lynn (Apr 6, 2009)

Hello there,

A few months ago I decided to go for a low tech approach and see if I could make my plants not die for a change. I set up this 6.6 gallon tank with 4 tiger barbs and 4 zebra danios, all juveniles. I put in some Elodeas, Hornwort, Anubias, and Vals. Everything went smooth except for some algae outbreak which was fixed with a water change and once the plants began to grow.

It seems that I had finally achieved the right balance between nutrients, lights, and plants. Plants seemed happy, fish seemed happy and most important, I was happy :fish:. I was using this HOB filter (without media) to create water movement. Well unfortunately one of my Danios swam into the filter meeting a horrible death. I removed it, but another jumped right in. Luckily this one didn't get cut up so I was able to save him. Needless to say, I replaced the HOB filter with a regular internal power head. 

My water parameters are within normal, so I would like to know if this death in my tank will affect its natural balance? Should I replace the zebra danio or just leave things as they are? I heard that I might even be a bit overcrowded, is that so?


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## Darksome (Feb 15, 2009)

It sounds just a tad bit overcrowded, a 6 gallon tank is a bit small for tiger barbs anyway...if you don't have media in your filter, I would put a plastic canvas cut to size to be able to fit in the media compartment...this will keep any fish from jumping in...I do this to keep snails out of my filter...and it works. I'm not too sure if replacing the dead fish will disrupt the balance in any way...so long as the new fish you get has the same bioload. I might be wrong.


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## Evil-Lynn (Apr 6, 2009)

yea, I was thinking the same. Maybe the danio died for a reason, I won't be replacing it. I'll be testing my water regularly to make sure everything remains OK considering the amount of fish I own.Thanks for your suggestion regarding the filter, I have changed it for a power head and now there is no way the fish can get hurt.


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## dwalstad (Apr 14, 2006)

Evil-Lynn said:


> yea, I was thinking the same. Maybe the danio died for a reason, I won't be replacing it. I'll be testing my water regularly to make sure everything remains OK considering the amount of fish I own.Thanks for your suggestion regarding the filter, I have changed it for a power head and now there is no way the fish can get hurt.


I think your fish load was (and is) fine. The better the total plant growth, the more fish you can have in a tank.

Too bad about the filter killing your fish. Your powerhead sounds like an improvement.

For a small tank, an airstone is probably all you really need. You mainly just want to gently circulate and aerate the water.


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## Evil-Lynn (Apr 6, 2009)

Thank you for your suggestion Diana. Indeed, I removed the power head and simply added an airstone. Surface agitation has improved. And well, the tank looks nicer and less crowded without having a filter or powerhead.

I am glad that my fish load is OK. I have one more question though, I feed my fish only once a day, would it be wiser to feed them twice a day instead? 

Thank you very much in advance.


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## Diana K (Dec 20, 2007)

I think the tank is overstocked, but for social reasons. Tiger Barbs are rather pushy fish, and the Danios that entered the filter may have been trying to get away from their nipping and harassing. 

If you want to feed half as much at each meal and feed twice a day, go for it.


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## Evil-Lynn (Apr 6, 2009)

Thanks for your insight Diana K. I as well initially believed we could be dealing with a bullying issue here but to be quite frank with you, I didn't witness any aggressive behavior from the part of the Barbs against the Danios. Moreover, the jumping into the HOB filter episode happened at night. My Barbs literally go to sleep as soon as the sun sets down.

I also read on different sites that Danios sometimes enjoy swimming against the current created by the HOB filter water fall. If the tank's water level is high enough, it's not uncommon for the little guys to manage to get inside the filter. That's what I think took place here.

Concerning my question about food, my aim is to see if I should increase the amount of food. I read that low tech tanks with healthy plant growth benefit from fish being fed "prodigally". So I basically want to know if I should add an extra meal to my fish considering that my plants are doing well and considering the amount of fish I have in the tank.:hungry:


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## Darksome (Feb 15, 2009)

That's what I referring to, what Diana K said, about the tank being too small for tiger barbs to swim about, of course yours are juveniles...then I agree with Diana Walstad, in lower tech tanks you can keep many more fish with a lot of plant growth so long as that does not compromise the well being of the fish...in other words, you can keep a lot more fish if they are small like danios. I have a lower tech tank and yes an extra meal (or two) doesn't hurt, you just have to make sure that you feed in small portions...never overdo it. With time I think you'll get the hang of it.


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## dwalstad (Apr 14, 2006)

I certainly recommend feeding fish twice a day. On weekends, mine get lunch, too!

If plants are truly growing well and you've got an airstone, I would definitely recommend feeding fish twice a day-- even if its just smaller portions. 

It would be nice to see a picture of this tank.


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## dianainOH (Mar 21, 2009)

Evil-lynn,
Not sure about your other issues, but I do know for a fact that danios like swimming up waterfalls (think salmon). Years ago I set up a 125 as a vivarium with a stream running the length of the tank into a 'pond' containing danios and a few snails. The pond was big enough for the danios, water quality was fine, and nothing was chasing them. The danios spent hours jumping up the small waterfalls in the stream, then riding back down and doing it again. It was wonderful to watch.


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## Evil-Lynn (Apr 6, 2009)

dianainOH:
Thanks for your input. That just about confirms my theory. My Danios and Barbs are doing well together now that I simply have an air pump in the tank. It must have been quite a spectacle watching your Danios jump against the current. 

dwalstad:
As of tomorow my fish will have brunch and dinner like you suggest 
Here are a couple of pictures with explanations so you can get an idea of my set up:









I get my light from my window. Only indirect sunlight. You can see the Elodeas have taken over. They really helped with algae issues I experienced the first couple of weeks. My two Vals got twice as big in 2 months, I have recently trimmed them so you can't see them much.

Here is a close up pic:








The black thing you see in the middle is some kind of slow growing moss, that is supposed to be really helpful when it comes to absorbing nutrients from the water column. Right next to it there is some Anubia Nana rhizome attached to a rock. No leafs are growing yet, but I noticed some substantial root growth in the past couple of weeks.

My tank is probably not as breathtaking as other low tech tanks, some people might find my anacharis cheap looking, even to be a plague but I like them. I managed to keep my fish and plants healthy except my hornwort which kept shredding so I got rid of it. Either way, Diana W. your system has turned fishkeeping into a most pleasurable experience for me, so I want to thank for sharing your knowledge.


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## jschall (Apr 13, 2009)

Evil-Lynn said:


> dianainOH:
> Thanks for your input. That just about confirms my theory. My Danios and Barbs are doing well together now that I simply have an air pump in the tank. It must have been quite a spectacle watching your Danios jump against the current.
> 
> dwalstad:
> ...


Looks great.


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## melauriga (Mar 20, 2009)

My tank is probably not as breathtaking as other low tech tanks, some people might find my anacharis cheap looking, even to be a plague but I like them. I managed to keep my fish and plants healthy except my hornwort which kept shredding so I got rid of it. Either way, Diana W. your system has turned fishkeeping into a most pleasurable experience for me, so I want to thank for sharing your knowledge.[/QUOTE]

Yes, some people look down on the easier plants. I think any tank with healthy plant growth is beautiful. In my opinion a lot of the Walstad tanks, which are often jungley and less manicured, are the underwater equivalent of cottage gardens. The carefully planned aquascapes of the high-tech tanks are more like formal gardens. Either one has its own appeal. I have a higher tech tank that I am more careful about plant placement. I am just starting an NPT and kind of looking for the wilder, more natural look with that. Anyway, I think your tank looks just fine and the plants are apparently doing what they are intended to.


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## Evil-Lynn (Apr 6, 2009)

Thank you melauriga and jschall


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## dianainOH (Mar 21, 2009)

Evil-lynn, yes it was great fun to watch. I wish I still had that tank. It was one of my favorites ever.
I really like your tank. Simple and pretty. I would be a little worried about the table you have it on, though. Water weighs 8 1/2 lbs per gallon, which makes even a small tank extremely heavy. I would put a piece of wood under the tank that is supported by the edges of the table rather than the glass. It wouldn't take much for that table top to crack with all of that weight on it.


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## Evil-Lynn (Apr 6, 2009)

dianainOH said:


> Evil-lynn, yes it was great fun to watch. I wish I still had that tank. It was one of my favorites ever.
> I really like your tank. Simple and pretty. I would be a little worried about the table you have it on, though. Water weighs 8 1/2 lbs per gallon, which makes even a small tank extremely heavy. I would put a piece of wood under the tank that is supported by the edges of the table rather than the glass. It wouldn't take much for that table top to crack with all of that weight on it.


Thank you for your suggestion. The glass of that table is pretty thick and it was able to handle a 20 gallon tank for nearly 5 years. It's got some kind of wooden support underneath. I haven't had much problems with this small 6,6 gallon tank, I placed some sponges below the edges to avoid glass scratching/cutting.

Since my last post there has been some changes:
-The moss was losing too many leafes so I had to remove it. Since I was unable to identify it, I didn't know how to care for it properly. My guess is that it needed less light and more heat.
-My val got huge after trimming, it even produced baby vals which I separated from the mother and replanted. They are growing slowly but seem healthy.
-I have noticed the presence of some cyanobacteria on the gravel. It seems to grow very slowly, but I have trimmed some elodeas to create more plants which will soon outcompete the cyanobacteria for food. Hopefully!
- My friend started his own 10 gallon El Natural style tank with some barbs and some plants I gave him from my tank. I gave him 2 of my tiger barbs, he has 3 green barbs, all are schooling together. I still have 2 barbs and i bought myself a pair of zebra danios. All get along just fine and seem healthy. In total I own 5 zebra danios and 2 tiger barbs. I noticed one tiny snail which I will leave alone unless it starts munching on my healthy plants!

Sorry if this post was kinda long and boring but I get excited about my tank and I felt like sharing what's going on with it, those who are interested anyways. 
Cheers!:wink:


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## dwalstad (Apr 14, 2006)

Evil-Lynn said:


> Sorry if this post was kinda long and boring but I get excited about my tank and I felt like sharing what's going on with it, those who are interested anyways.
> Cheers!:wink:


Sounds like you and your friend are having fun with your tanks. That's great!

One caution: I would be careful about the pepples and stones in the tank. Food and organic debris can easily get trapped between the stones, rot anaerobically, and pollute the water. You may need to clean the substrate from time-to-time, especially if your fish show any loss of appetite.

That said, I like this small tank with inexpensive plants.


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## Evil-Lynn (Apr 6, 2009)

dwalstad said:


> Sounds like you and your friend are having fun with your tanks. That's great!
> 
> One caution: I would be careful about the pepples and stones in the tank. Food and organic debris can easily get trapped between the stones, rot anaerobically, and pollute the water. You may need to clean the substrate from time-to-time, especially if your fish show any loss of appetite.
> 
> That said, I like this small tank with inexpensive plants.


I haven't actually thought of that! I use some pebbles just to attach some plants to the bottom. Should I vacuum the areas where the pebbles are located once a week? This would imply a small water change, do you think it would have a negative effect on the CO2 levels? I mean I am also using a small air pump.

Another update on the tank: I am letting my vals take over the surface. I will do the same with the elodeas since I hear this is good. Fish wise, I gave my two tiger barbs to my friend, I think they'd be happier in a 100 % barb tank. I am keeping only 4 zebra danios which I feed twice a day. All looks good thus far, no major problems. The Cyanobacteria has stopped spready or it just spreads quite slowly...


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## Elliabel (Jun 3, 2009)

I like your tank Lynn, it looks pretty and healthy. Other plants are more expensive because they are hard to find and hard to keep alive. Doesn't mean they are prettier than cheap ones...

I have been doing some research the whole afternoon about anaerobic substrate. Diana has a point: a lot of people advice not to place too many rocks or pebbles because of the reasons she stated in her post. 

Nevertheless, you mention you use the pebbles the attach the anacharis to the bottom of the tank. I assume you simply place a pebble on top of the lower part of the plant. Now, I read that these kinds of plants are excellent oxygen providers. So wouldn't these plants also provide oxygen underneath the pebbles? thus keeping them aerobic?

I also read a post that said if you are placing a rock it's best to do it where there is no gravel or soil, on plain glass so to speak. Is this true? If it is you might try doing that, if you don't mind the risk of creating a muddy mess...


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## Evil-Lynn (Apr 6, 2009)

You bring out an interesting point Elliabel. I suppose the area bellow the pebble won't go anaerobic as long as the plant remains healthy. I will prune it if I see turn it brown or losing leafs.

On a sadder note one of my danios appeared dead today  her belly was very swollen and the last couple of days she kept being chased by the other fish. I think they were trying to mate and she was carrying eggs and maybe died from the stress of being poked by the males. I am thinking she also might have died from the effort of laying eggs, since her corpse had a flat stomach. I don't see the eggs though, I don't know what they are supposed to look like. Now my tank looks empty after I gave my barbs to my friend I only got 3 zebra danios left. I think I will leave it like that, considering they have some growing to do. And they only have 6.6 gallons to swim about...

My water parameters are on the safe side. I will keep a close look to see if there are eggs or fry in the next couple of days.


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## Elliabel (Jun 3, 2009)

I am sorry about your loss Lynn. I actually heard that many females die from stress while giving birth/laying eggs. My friend has a 30 gallon tank with tons of guppies. The females normally die from the effort of giving birth to fry. I assume laying eggs requires also a great deal of effort.
If your fish died from that, the other surviving fish probably ate all the eggs. You'll know if you spot fry by tuesday at the latest.

You say you have a nano tank, only 6.5g or so big. I wouldn't add more fish there, not because of water quality issues since your tank is low tech, but for space issues. Your danios will grow up to 3 inches and are pretty active. I would still feed them well twice a day though...

I am setting up my 10g tank this after noon. I have bought frogbit, elodeas, water lettuce, java moss, and watersprite. I will just add a thin layer of sand and gravel like Diana recommended in my other thread. I will populate it with 4 black male mollies. I don't wanna have to deal with baby fish!
Wish me luck!
Cat.


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## Evil-Lynn (Apr 6, 2009)

danios will grow up to 3 inches and are pretty active. I would still feed them well twice a day though...
Cat.[/QUOTE said:


> Yea originally I made this thread concerned about excess of nutrients but apparently the real issue would be space for the fish to move easily (reason why I gave away the tiger barbs). I wouldn't want them to bump into things or into eachother. As it turns out, I have a male danio plus two females. I am not concerned about them having babies since they will eat the eggs and fry most likely, I just don't want the females to die in labor. They are pretty small comparing to the male so mayby that is why this one died: too many eggs. I didn't know Nano tanks could be difficult regarding population issues...
> 
> Either way, if Diana stated on your thread that the set up you plan on doing worked for her it should work for you too! Your plant choice is excellent: none of the plants needs soil and they are all very pretty. Specially watersprite which I am thinking of using in the future. However, I wouldn't call it a NPT since you won't use any soil. If you only have 4 black mollies in a 10 gallon tank, feeding them twice a day would be good, the frogbit and water lettuce will love it! Just make sure they don't cover the whole surface so the plants at the bottom get enough light.


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