Is fish tank filter cartridges profitable to sell on Amazon United Kingdom?

The niche generates £75K/yr across 39 tracked products. 0 of 5 products launched in the last 360 days are still selling. 90-day search growth is -27.2%. Flapen's verdict: Worth a look (52/100).

How competitive is the fish tank filter cartridges niche?

18 brands and 68 sellers compete. The top 5 products take 45% of clicks and top 5 brands hold 84% of demand.

What do buyers complain about in fish tank filter cartridges?

Top complaints mined from reviews: Filtration, Quality-Overall, Size-Overall. The return rate is 0.8%.

When does demand for fish tank filter cartridges peak?

Demand peaks in Feb; the busiest month runs 1.6× the quietest.

What does it cost to enter the fish tank filter cartridges niche?

Listings span £2.73–£28.59; the average listing price is £10.91 (sweet spot $15–$100). The average incumbent carries 841 reviews — the moat a new listing must climb.

fish tank filter cartridges

Worth a look

Shows low returns (0.8%), but soft demand (-27.2% this quarter) keeps it on the watch list.

Returns

Incredible0.8%

return rate — above 5% kills the launch gate

Conversion

Great11.1%

search→purchase rate — share of searches ending in a sale

Quality gap

Good4.3★

avg incumbent rating — lower means beatable quality

Competition

Good45%

top-5 click share — leaders hold, buyers still browse

Review moat

Good840.54

avg incumbent reviews — the moat a new listing must climb

Price range

Good£2.73–£28.59

cheapest to priciest tracked listing — scored on the share inside $15–$100

Avg price

Okay£10.91

avg listing price — sweet spot $15–$100

Brand share

Okay84%

top-5 brand share — brands hold most of the demand

Market size

Bad£75K

£75K/yr · 61K searches

Growth

Bad-27.2%

90-day search growth — must beat 0% to launch

According to Flapen's Amazon United Kingdom niche tracking, fish tank filter cartridges is a £75K/yr Amazon United Kingdom market (61K searches/yr). The top 5 brands hold 84% of demand. Demand peaks in Feb. Verdict: Worth a look — 52/100.

Data updated Jul 29, 2026 · scored weekly · How we score niches

fish tank filter cartridges market data

Units sold / yr: 5K–6K; avg 100–250/product
Revenue / yr: £55K–£65K; units × avg price
Conversion rate: 11.1%
Avg BSR: #132
Page quality: 0%
Prime: 74%
Sponsored: 51%
Out of stock: 2.2%
Avg brand age: 35 months
Avg seller age: 179 days

Competition & brand share

The top 5 products take 45% of clicks — established leaders, but buyers still shop beyond them.

Brands

18 rising

Sellers

Top-5 brand share

84%

Top 20: 100%

Top-5 click share

45%

Top 20: 85%

Open market

13%

Ciano36%
Finest-Filters23%
Interpet11%
Tetra9%
Marina5%
CWA2%
Open — no brand owns it (12 brands, 13%)

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — -27.2% search growth over the last 90 days.

Peak months: Feb · busiest ÷ quietest = 1.6×

Open Trend

Top fish tank filter cartridges search terms

ciano fish tank filter cartridges15K/yr -24.8%10.7% conv.
fish tank filter cartridges16K/yr -40.6%6.1% conv.
ciano filter7K/yr +8.0%5.8% conv.
tetra filter6K/yr -32.1%5.4% conv.
interpet cf1 filter 3 month service kit5K/yr -15.3%11.2% conv.
ciano4K/yr -28.9%3.8% conv.
cf1 filter service pack 3 month4K/yr -38.7%10.5% conv.
fish filter cartridges2K/yr -4.2%7.8% conv.
tetra easy crystal filter 250/3002K/yr -37.3%11.2% conv.

All search terms

Top fish tank filter cartridges products on Amazon

Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 24 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

Interpet 3 Month Service Pack for the Interpet Internal Cartridge Filter CF1 (3 x Filter Cartridge 3 x Algaway Pad) clear

Interpet£5.304.5★3,080 rev

Finest-Filters Compatible with Ciano Water Clear & Protect CF20 CF40 Aquarium Filter Media - Water Clear Cartridge S (2 Pack)

Finest-Filters£5.314.4★65 rev

CIANO AQUARIUM FILTER MEDIA REPLACEMENT SET - SMALL / CF40

Ciano£19.664.5★455 rev

CIANO Aquarium Consumables Replacement Filter Cartridges for Aquarium Filter Pack 3 Months Size S Crystal Water for Fish Impurity-Free and Odourless Effective Cleaning

Ciano£17.203.8★35 rev

CIANO AQUARIUM FILTER MEDIA - WATER CLEAR CARTRIDGE SM / CF40 X2

Ciano£7.434.5★1,247 rev

Newest

by launch date

Finest-Filters Compatible with Interpet Internal CF Cartridge Filters - Fish Tank Filter Cartridges Interpet Filter CF1Filter Service Pack 3 Month Multiple Pack (3Filter Cartridges and 3 Pads)

Kaelosyn£4.965 rev

4mo ago

beaufan 14 Set Filter Cartridges - Compatible with Tetra EasyCrystal Filter 250 & FilterBox 300 Aquarium Filters | Replacement for Tetra Whisper Internal Power Filter (5-10 Gallons)

beaufan£15.4814 rev

7mo ago

DXPETA CF1 Filter Service Pack 4 Fish Tank Filter Cartridges and 4 Green White Pads Compatible with Interpet CF1 Internal Filters Small Aquarium Filter Replacement

DXPETA£8.652 rev

11mo ago

Haliya 3 Month Service Kit Compatible with Interpet CF1 Filter

Haliya£5.9966 rev

1y ago

Finest-Filters Compatible with Ciano Water Clear/Bio Bact/Stop Algae CF20 CF40 Aquarium Filter Media Cartridge S Full Set (6 Pack)

Finest-Filters£13.0011 rev

1y ago

What buyers say about fish tank filter cartridges

What buyers praise and complain about, mined from review topics.

What buyers love

Value For Money23%

“Good value”

Filtration17%

“Budget friendly good quality filter”

Quality-Overall14%

“As good as the branded. but cheaper”

Size-Overall12%

“Fit well”

Advertised Vs Actual Product11%

“AS DESCRIBED”

Ease Of Cleaning6%

“it's easy to clean”

Ease Of Use3%

“Easy use”

Water Flow2%

“The water is clear”

Spray/Flow2%

“the water flow is effective”

Efficiency1%

“100% Works for cleaner water”

What buyers complain about

Filtration18%

“Worst filter I have ever seen”

Quality-Overall12%

“Cheap knock off version of a similar product, terrible quality, avoid”

Size-Overall12%

“Not fit for purpose”

Durability10%

“Doesn't last long”

Water Flow6%

“Hardly any flow”

Thickness5%

“Absolutely rubbish, they are way to thin and don't last”

Advertised Vs Actual Product4%

“False advertisement”

Value For Money4%

“I would not recommend cheap options”

Comfort-Overall3%

“its not relaxing at all”

Hard Feel3%

“Too fiddly”

Top return reasons

Size-Overall61%

Filtration12%

Compatibility-Overall6%

Functionality-Overall4%

Advertised Vs Actual Product4%

Defective Material/Parts3%

Quality-Overall2%

Strength2%

Durability1%

Product Condition1%

Common questions

Is fish tank filter cartridges profitable to sell on Amazon United Kingdom?: The niche generates £75K/yr across 39 tracked products. 0 of 5 products launched in the last 360 days are still selling. 90-day search growth is -27.2%. Flapen's verdict: Worth a look (52/100).
How competitive is the fish tank filter cartridges niche?: 18 brands and 68 sellers compete. The top 5 products take 45% of clicks and top 5 brands hold 84% of demand.
What do buyers complain about in fish tank filter cartridges?: Top complaints mined from reviews: Filtration, Quality-Overall, Size-Overall. The return rate is 0.8%.
When does demand for fish tank filter cartridges peak?: Demand peaks in Feb; the busiest month runs 1.6× the quietest.
What does it cost to enter the fish tank filter cartridges niche?: Listings span £2.73–£28.59; the average listing price is £10.91 (sweet spot $15–$100). The average incumbent carries 841 reviews — the moat a new listing must climb.