---
title: "Fish Tank Filter Cartridges — £75K/yr Amazon UK Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/uk/pet-supplies/fish-tank-filter-cartridges"
last_updated: "2026-07-31T10:29:01.032Z"
locale: en
meta:
description: "Niche score 52/100 · £75K/yr market · 61K searches/yr · £10.91 avg price. Soft demand (-27.2% this quarter) keeps it on the watch list. Data updated Jul 2026."
"og:description": "Niche score 52/100 · £75K/yr market · 61K searches/yr · £10.91 avg price. Soft demand (-27.2% this quarter) keeps it on the watch list. Data updated Jul 2026."
"og:title": "Fish Tank Filter Cartridges — £75K/yr Amazon UK Niche (2026) - Flapen"
---
# **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.
Market size 19Growth 11Conversion 92Competition 66Returns 96Price range 53Avg price 41Brand share 34Review moat 66Quality gap 73
**Returns**
**Incredible****0.8%**
return rate — above 5% kills the launch gate
**Conversion**
**Great****11.1%**
search→purchase rate — share of searches ending in a sale
**Quality gap**
**Good****4.3★**
avg incumbent rating — lower means beatable quality
**Competition**
**Good****45%**
top-5 click share — leaders hold, buyers still browse
**Review moat**
**Good****840.54**
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**
**Okay****84%**
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 ~~](https://flapen.com/research/methodology)
## **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**
**68**
**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.
2K1KSpike '24Black Friday '24Spike '26 seasonSepDecMarJunAugNovMarMay
Peak months: Feb · busiest ÷ quietest = 1.6×
[**Open Trend **](https://flapen.com/research/uk/pet-supplies/fish-tank-filter-cartridges/trend)
## **Top fish tank filter cartridges search terms**
- **ciano fish tank filter cartridges**15K/yr-24.8%10.7% conv. - **fish tank filter cartridges**16K/yr-40.6%6.1% conv. - **ciano filter**7K/yr+8.0%5.8% conv. - **tetra filter**6K/yr-32.1%5.4% conv. - **interpet cf1 filter 3 month service kit**5K/yr-15.3%11.2% conv. - **ciano**4K/yr-28.9%3.8% conv. - **cf1 filter service pack 3 month**4K/yr-38.7%10.5% conv. - **fish filter cartridges**2K/yr-4.2%7.8% conv. - **tetra easy crystal filter 250/300**2K/yr-37.3%11.2% conv. [**All search terms **](https://flapen.com/research/uk/pet-supplies/fish-tank-filter-cartridges/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.
0%3%£2K6%£4K9%£7K12%£9K1101001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
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
[1**Interpet 3 Month Service Pack for the Interpet Internal Cartridge Filter CF1 (3 x Filter Cartridge 3 x Algaway Pad) clear**Interpet**£5.30**4.5★3,080 rev](https://www.amazon.co.uk/dp/B00HGEDL6I) [2**Finest-Filters Compatible with Ciano Water Clear & Protect CF20 CF40 Aquarium Filter Media - Water Clear Cartridge S (2 Pack)**Finest-Filters**£5.31**4.4★65 rev](https://www.amazon.co.uk/dp/B0F2LDPVWJ) [3**CIANO AQUARIUM FILTER MEDIA REPLACEMENT SET - SMALL / CF40**Ciano**£19.66**4.5★455 rev](https://www.amazon.co.uk/dp/B01IM04CPS) [4**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**£17.20**3.8★35 rev](https://www.amazon.co.uk/dp/B07D14HY1Q) [5**CIANO AQUARIUM FILTER MEDIA - WATER CLEAR CARTRIDGE SM / CF40 X2**Ciano**£7.43**4.5★1,247 rev](https://www.amazon.co.uk/dp/B01HEX9M9K)
**~~View all top sellers →~~**
### **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**£4.96**5 rev4mo ago](https://www.amazon.co.uk/dp/B0GSFDMX43) [**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**£15.48**14 rev7mo ago](https://www.amazon.co.uk/dp/B0G52GP8GK) [**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**£8.65**2 rev11mo ago](https://www.amazon.co.uk/dp/B0FP9C1NFX) [**Haliya 3 Month Service Kit Compatible with Interpet CF1 Filter**Haliya**£5.99**66 rev1y ago](https://www.amazon.co.uk/dp/B0F632DBDH) [**Finest-Filters Compatible with Ciano Water Clear/Bio Bact/Stop Algae CF20 CF40 Aquarium Filter Media Cartridge S Full Set (6 Pack)**Finest-Filters**£13.00**11 rev1y ago](https://www.amazon.co.uk/dp/B0F35PDF9F)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**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**£4.96**2.8★**▲ 313%**](https://www.amazon.co.uk/dp/B0GSFDMX43) [**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**£15.48**4.6★**▲ 200%**](https://www.amazon.co.uk/dp/B0G52GP8GK) [**CIANO Aquarium Consumables Replacement Filter Cartridges for Aquarium Filter Pack 3 Months Size M Crystal Water for Fish Impurity-Free and Odourless Effective Cleaning**Ciano**£26.01**3.5★**▲ 70%**](https://www.amazon.co.uk/dp/B07D149JRB) [**Finest-Filters Compatible with Ciano Water Clear/Bio Bact/Stop Algae CF20 CF40 Aquarium Filter Media Cartridge S Full Set (6 Pack)**Finest-Filters**£13.00**3.4★**▲ 61%**](https://www.amazon.co.uk/dp/B0F35PDF9F) [**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**£8.65**5.0★**▲ 50%**](https://www.amazon.co.uk/dp/B0FP9C1NFX)
**~~View all trending →~~**
## **What buyers say about fish tank filter cartridges**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Value For Money**23%
*“Good value”*
**Filtration**17%
*“Budget friendly good quality filter”*
**Quality-Overall**14%
*“As good as the branded. but cheaper”*
**Size-Overall**12%
*“Fit well”*
**Advertised Vs Actual Product**11%
*“AS DESCRIBED”*
**Ease Of Cleaning**6%
*“it's easy to clean”*
**Ease Of Use**3%
*“Easy use”*
**Water Flow**2%
*“The water is clear”*
**Spray/Flow**2%
*“the water flow is effective”*
**Efficiency**1%
*“100% Works for cleaner water”*
### **What buyers complain about **
**Filtration**18%
*“Worst filter I have ever seen”*
**Quality-Overall**12%
*“Cheap knock off version of a similar product, terrible quality, avoid”*
**Size-Overall**12%
*“Not fit for purpose”*
**Durability**10%
*“Doesn't last long”*
**Water Flow**6%
*“Hardly any flow”*
**Thickness**5%
*“Absolutely rubbish, they are way to thin and don't last”*
**Advertised Vs Actual Product**4%
*“False advertisement”*
**Value For Money**4%
*“I would not recommend cheap options”*
**Comfort-Overall**3%
*“its not relaxing at all”*
**Hard Feel**3%
*“Too fiddly”*
### **Top return reasons **
**Size-Overall**61%
**Filtration**12%
**Compatibility-Overall**6%
**Functionality-Overall**4%
**Advertised Vs Actual Product**4%
**Defective Material/Parts**3%
**Quality-Overall**2%
**Strength**2%
**Durability**1%
**Product Condition**1%
## **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.
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