Shy Tiger Barbs

Hope someone can help.

I had a well established tank with some cichlids in for a number of years. Through time and natural wastage the number of fish dwindled to just a jewel and a rainbow cichlid. Wanting to restock the tank I took the step of rehoming the remaining two fish and changing tack with what I had in the tank.

So I have moved away from cichlids and put Tiger Barbs in the tank (thought it might make a nice change) ... They are the only fish in the tank now.

The Barbs are young fish at the moment (about 1/2" long) and I have a shoal of 20 (a half and half split with green Tiger Barbs and normal orange Tiger Barbs)

When I first put them in the tank after a period of acclimatisation they swam around the tank in a large group and looked very happy. However, a day later it is as if the tank is completely empty. They have all taken to hiding under the plants at the back of the tank.

The tank has remained the same (well planted, well filtered, regular water changes, virtually no algae, good water quality with PH levels and ammonia levels) It has twin T5 daylight lighting strips, which are on a timer which puts the lighting on and off throughout the day (the longest "on" period is in the evening when we're home)

I am assuming the fish are just "getting used to" their new home (???) Is that correct? Does anyone have a similar experience?

Any pointers would be appreciated ...

Welcome to TFF!

Good water quality means nothing Always give the exact numbers. What is your tank size? Temp? Can you show us a picture of the whole tank? Overall, if they swim and breath normally, and feed then I would not be too worried yet and give them some more time to settle in.

hobby5 said:

Welcome to TFF!

Good water quality means nothing Always give the exact numbers. What is your tank size? Temp? Can you show us a picture of the whole tank? Overall, if they swim and breath normally, and feed then I would not be too worried yet and give them some more time to settle in.

Click to expand...

thanks for the response. Sorry, I thought I'd put sizes etc in the original post ... 250lt tank so plenty of space to move around with 20 new tiger barbs. Sorry I don't have a photo to hand to upload but it has plenty if greenery, wood and stone to aquascape the tank. As I say its a well established tank not a brand new setup.

guessing I need to give them a bit of space and time ( I may reduce the amount of time the lights are on during the day )

let's see how it goes over the next couple of days

hi there ... Attached is a photo of the tank.

I came home this evening and still no sign of any fish I'm the tank I'm pretty sure I put them in there ...

so I dropped some food in to see if I could get them out of hiding ... Sure enough the plants explode with a shoal of tiger barbs ...

they are still keeping very close to the floor of the tank and around where the cover is, bit it was nice to see them feed at last (its been nearly 5 days since I put them in, and this is the first time I've watched them eat)

guessing they do just need to get used to the tank after al... Phew.

had a swift check on the ones I could see and they all look healthy

There can be several factors involved here, but you do have issues with the light that could easily be relevant. T5 light is very bright, and floating plants are important. There is also the light period fluctuation which is detrimental. I answered this in detail in another thread, so I will just copy that. Feel free to ask any questions.

The Day/Night Cycle

Most animals have an internal body clock, called a circadian rhythm, which is modified by the light/dark cycle every 24 hours. This is the explanation for jet-lag in humans when time zones are crossed—our circadian rhythm is unbalanced and has to reset itself, which it does according to periods of light and dark. Our eyes play a primary role in this, but many of our body cells have some reaction to light levels. In fish this light sensitivity in their cells is very high.

The rods and cones in the eye shift according to the changes in light. This process is also anticipated according to the time of day; the fish “expects” dawn and dusk, and the eyes will automatically begin to adjust accordingly. This is due to the circadian rhythm.

This is one reason why during each 24 hours a regular period of light/dark—ensuring there are several hours of complete darkness—is essential for the fish. In the tropics, day and night is equal for all 365 days a year, with approximately ten to twelve hours each of daylight and complete darkness, separated by fairly brief periods of dawn or dusk. The period of daylight produced by direct tank lighting can be shorter; and the period of total darkness can be somewhat shorter or longer—but there must be several hours of complete darkness in the aquarium. The dusk and dawn periods will appear to be stretched out, but that causes no problems for the fish. It is the bright overhead light that is the concern, along with having a suitable period of total darkness. And the "day" period when the tank lights are on should be one continuous period, not sporadic, and it should be the same every 24 hours or it will impact the circadian rhythm causing more stress.

The Brightness of the Tank Light

“Daylight” can be vastly different for different species of fish, depending upon their natural habitats. Most aquarium fish are forest fish, living in rivers, streams and creeks, ponds and small lakes, and even ditches and swamps. Some of these watercourses are permanently shaded by the forest canopy or overhanging marginal vegetation; some are filled with branches and sunken bogwood; some watercourses are white-water, full of suspended particulate matter that “soaks up” the light and keeps the water murky and dimly lit; watercourses in full sunlight usually have a thick mat of floating plants, and depending upon the position of the sun in the sky, much of its light may be reflected off the surface. In most areas of the tropics, the rivers and streams rise and flood the surrounding forest for half the year, and it is during this period that the fish move into the even darker forest waters to spawn. For fish living in all of these environments, bright light is something they seldom—and in some cases never—experience, or from which they prefer to retreat given the opportunity. It is no surprise that the fish in the brightly-lit watercourses are almost always found at the edge under overhanging vegetation, branches and outcrops, or floating vegetation.

Programmed by nature over millions of years for such dimly-lit environments, the eyes of a fish are designed to capture the maximum amount of light. This allows the fish to have some degree of vision even in dimly-lit water. But when placed in brighter light, the fish will naturally look for cover in order to escape from that light. Aquarists can readily see this in the aquarium; many forest fish when given the option clearly prefer shaded areas. Baensch & Riehl (1987) called it a “light phobia” in characins.

thanks for such a detailed response. Just to clarify around the light cycle. There is a period over night of nearly 11 hours where the tank is dark, so there is (almost) a half and half day to night ratio. The cycle turns the lights off for a couple of hours over lunch time (ish)

I take on board the issue with the T5's ... They were always in the tank when I had the cichlids and never caused an issue. I like the idea of floating plants so may have to invest.

this evening they came out to eat, which is a start.

pdlawson said:

thanks for such a detailed response. Just to clarify around the light cycle. There is a period over night of nearly 11 hours where the tank is dark, so there is (almost) a half and half day to night ratio. The cycle turns the lights off for a couple of hours over lunch time (ish)

I take on board the issue with the T5's ... They were always in the tank when I had the cichlids and never caused an issue. I like the idea of floating plants so may have to invest.

this evening they came out to eat, which is a start.

Click to expand...

I may not be fully understanding the light issue (para 1)...just to be clear, you do not want the tank light coming on more than one continuous period each day. The so-called "siesta" method with planted tanks is bad for the fish. You can have this "daylight" whenever you like, so long as it is continuous. When I was working, leaving the house before 7 am and getting home around 6 pm, I had the tank lights come on at 1 pm and go off at 9 pm. This provided a period of 8 hours "daylight" which was the max to control algae, but it provided me with the longest period to enjoy the tanks, given my schedule. Now I'm retired, the tank lights are on at 9:30 am and off at 5:30pm. The single period of tank lighting is critical.

☺ just to clarify what I was trying to say. The lights come of @10am ... Switch off @ midday for a couple of hours, and then are on till 10pm ... Then off again until 10am the next day (so 12 solid hours of "darkness") ... The room the tank is in is in the middle of the house and has no external windows so is not overly bright during the day.

I understand the point around a continuos lighting so will give it a try ... We are around later in the day so will switch the schedule to accommodate this and try it out

pdlawson said:

☺ just to clarify what I was trying to say. The lights come of @10am ... Switch off @ midday for a couple of hours, and then are on till 10pm

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This is what I was afraid of, it is the "Siesta" approach, not good so changing to one continuous period (coming on later is fine) will solve this.

You have strong lighting, so algae may be an issue. The "siesta" approach is intended to solve the CO2 issue, by providing a period of no light in between two periods of light, thus allowing the CO2 to rebuild. However, when it comes to fish health, plants must take second place, in my mind anyway. These siestas are fine in fishless tanks.

thanks for all the replies and updates ... Much appreciated .... Light schedule changed (10 hours on, 14 hours off)

I'll invest in some floating plants next time I'm down the local shop.

algae isn't much of a problem at the moment, but once the tiger barbs were settled in I was going to invest in a couple of algae eaters ... Not sure which yet (bristle nose pleco, panda garra or something along those sort of lines)

pdlawson said:

thanks for all the replies and updates ... Much appreciated .... Light schedule changed (10 hours on, 14 hours off)

I'll invest in some floating plants next time I'm down the local shop.

algae isn't much of a problem at the moment, but once the tiger barbs were settled in I was going to invest in a couple of algae eaters ... Not sure which yet (bristle nose pleco, panda garra or something along those sort of lines)

Click to expand...

You might want to consider less light period; I found with my T8 lighting (which is considerably less intense than T5) that 8 hours is max, and 7 hours in my 70g. With this schedule, the additional daylight in the summer can create sudden algae issues, which only shows how sensitive the balance can be.

Problem algae unfortunately can't be helped by so-called algae eating fish, and ironically it is always the problem algae that occurs with too strong or too long a photoperiod. Brush algae is the one I have to contend with if the light/nutrient balance gets out, and nothing will eat this (except two fish species which would be unsuitable in my tanks anyway).

Just for illustration, here's a photo of my biotope tank for the Black Ruby Barb, not the Tiger but a relative. This species (Pethia nigrofasciata) is endemic to the Kelani and Nilwala river basins on Sri Lanka, and I was able to replicate the habitat nearly exactly.

Byron.

Just to close this off and give an update on the tank.

For years I kept Cichlids in the tank. If I ever added a new fish, after a couple of hours they had settled in and owned the tank.

I took the decision to change the tank usage from Cichlids to a school of Tiger barbs. After 2 days of having the barbs in the tank, they all hid at the bottom, and rarely came out to feed.... hence the post.

I did change the lighting schedule as per some of the comments above, and I'm not sure whether it helped or I was just being too hasty while expecting the Barbs to settle in as quickly as the Cichlids. I still have the T5 tubes in the tank, and haven't added any floating plants as yet.

Day 1-2 no sign of any fish
Day 3-4 the odd one would pop out, but stuck to the bottom of the tank. They would wait for the food to drift down.
Day 5-7 All fish swimming around the bottom third of the tank. Coming to the surface to feed now. Still very skittish
Day 8-10 Tiger barbs behaving like tiger barbs should. they are flying around the tank, playing games and feeding like they have never been fed before. They will come to the front of the tank now and follow me expecting to be fed.

Lesson learned ... Tiger barbs take longer to settle in than Cichlids. Tank is looking very good now.

I'm going to leave it for another month to settle in to a cycle then will look at the possibility of algae eaters (currently leaning towards a couple of Panda Garra's)

thanks for the comments

Just give them some time. They will come out. It just takes time. It is a new tank and they are scared. My two bettas did not come out of hiding for 3-4 days.

Byron said:

You might want to consider less light period; I found with my T8 lighting (which is considerably less intense than T5) that 8 hours is max, and 7 hours in my 70g. With this schedule, the additional daylight in the summer can create sudden algae issues, which only shows how sensitive the balance can be.

Problem algae unfortunately can't be helped by so-called algae eating fish, and ironically it is always the problem algae that occurs with too strong or too long a photoperiod. Brush algae is the one I have to contend with if the light/nutrient balance gets out, and nothing will eat this (except two fish species which would be unsuitable in my tanks anyway).

Just for illustration, here's a photo of my biotope tank for the Black Ruby Barb, not the Tiger but a relative. This species (Pethia nigrofasciata) is endemic to the Kelani and Nilwala river basins on Sri Lanka, and I was able to replicate the habitat nearly exactly.

Byron.

Click to expand...

That looks amazing ....and cozy!