For over two decades, Monster Pets has built a reputation as a leading seller in the pet supplies space. What started as a brick-and-mortar operation in South Philadelphia has evolved into a high-volume ecommerce business, now processing approximately 100,000 units per week and ranking among the top Amazon sellers in the pet category.
We spoke with Brian Fennell, Owner of Monster Pets, to understand how the company has scaled so efficiently and which tools have played a pivotal role in improving profitability, visibility, and operational speed.
Monster Pets began its journey 24 years ago as a traditional retail pet store. Over time, the business expanded into ecommerce, starting with eBay before moving into Amazon’s vendor model and eventually transitioning to Seller Central.
Today, ecommerce makes up nearly all of the company’s revenue.
“We actually started 24 years ago in brick and mortar. At one point we had three stores, but now we’re back to one in South Philadelphia. From there, we moved into eBay, then Amazon vendor, and now Seller Central. At this point, 98% of our business is online—primarily Amazon, but also Walmart and eBay, and we recently launched our own site.”
Unlike many sellers who focus on a narrow catalog, Monster Pets operates at scale with a highly diversified assortment.
“We’re not a typical seller. We have about 4,500 active SKUs that we replenish weekly. It’s a very high-velocity, on-demand model.”
Prior to 2026, Monster Pets relied on a combination of QuickBooks and marketplace reports, along with a third-party tool to try and understand their profit margins.
“We were pulling reports manually, sorting through them, and trying to piece everything together. We also used HelloProfit, but it just wasn’t sophisticated enough for what we needed.”
This approach created major blind spots, especially at scale.
“The biggest challenge was true profitability. When you’re doing our kind of volume, it’s very difficult to wrap your arms around what’s actually happening. You think an item is profitable, sometimes very profitable, but you’re not accounting for returns, reimbursements, Amazon adjustments, or damaged goods. Those things weren’t tied directly to the data we were looking at.”
As a result, products that appeared profitable on the surface were quietly eroding margins.
“You don’t realize how much those factors impact a product, especially larger or bulkier items where you expect strong margins. A handful of returns in a given week could completely wipe that out, and we had no clear way to see it.”
After switching to ConnectBooks, Monster Pets gained a much clearer, more accurate view of performance at the SKU level.
“I am over the moon with ConnectBooks. They are fantastic! The transparency it brings to our business is a game changer. Being able to drill all the way down to the ASIN level and see true performance… I don’t think there’s anyone else that does it like this, especially at our scale.”
This level of visibility has directly impacted decision-making across the business.
“It really shines a light on what’s actually profitable and what’s not. You can immediately identify underperforming SKUs. The ones that aren’t working don’t go back into inventory, or we reduce quantities significantly. That alone has driven our margins up.”
The platform has also become an essential part of daily operations.
“It’s the second tab I open every morning after Amazon. I’m constantly looking at performance: what’s working, what’s not, what’s most profitable. It’s all right there, and it’s incredibly user-friendly.”
Beyond day-to-day visibility, ConnectBooks has been integrated into Monster Pets’ broader purchasing and inventory workflows.
“We’ve actually built ConnectBooks into our buying process. We have proprietary software and ConnectBooks is a key input. It adds another level of intelligence when we’re deciding what to reorder and what to cut.”
While ConnectBooks brought financial clarity, ZonPrep transformed Monster Pets’ operational efficiency, particularly when it comes to speed to market.
“ZonPrep has been a game changer for us. We’ve cut at least 14 days out of our pipeline, sometimes closer to 20. When you’re moving inventory at our scale, that’s huge.”
Faster turnaround times have had a direct impact on cash flow and inventory performance.
“Saving those days in the pipeline improves cash flow immediately. Speed is everything in this business.”
ZonPrep also helped Monster Pets dramatically reduce costly Amazon Placement fees.
“We’ve basically eliminated placement fees. That was one of the biggest wins. At one point, we were paying six figures in monthly fees and now it’s almost zero. Last month it was under $1,000, which is nothing compared to where we were.”
Additionally, ZonPrep’s processes have improved efficiency inside Monster Pets’ own warehouse.
“We adopted parts of their process internally: hand scanners, real-time labeling, picture confirmations. It’s faster, more automated, and less labor-intensive. We’ve reduced labor costs and even cut supply costs by about 60% by reusing manufacturer packaging.”
While ConnectBooks and ZonPrep solve different problems, together they create a powerful advantage.
“They really are standalone solutions, but when you use them together, it’s incredibly powerful. ZonPrep gives you speed and cost savings. ConnectBooks gives you clarity. When you combine the two, you can see everything at the ASIN level—from how fast something gets to market to how profitable it actually is.”
This combination has helped Monster Pets optimize both top-line growth and bottom-line performance.
“You’re not guessing anymore. You’re making decisions based on real data. That’s the difference.”
For sellers considering tools like ConnectBooks, Brian is direct about the return on investment.
“It pays for itself almost immediately. Within the first week, you’re going to have that ‘oh my God’ moment where you realize what you’ve been missing. The insights you get can be worth a lot of money.”
He also emphasizes the importance of staying proactive in an ever-changing marketplace.
“Amazon changes constantly: fees, rules, competition. If you’re not paying attention to your numbers every day, you can lose money fast. Tools like ConnectBooks aren’t optional, they’re a necessity.”
Monster Pets’ success is built on operational discipline, data-driven decision-making, and a willingness to invest in the right tools. By combining the financial visibility of ConnectBooks with the operational efficiency of ZonPrep, they’ve created a scalable model that continues to drive growth and profitability.
“People don’t know what they don’t know. We’ve been doing this a long time, and even we were surprised by what we uncovered. Having that level of clarity… it changes everything!”
For other ecommerce brands who are struggling with their limited visibility as they scale, or restrictive and expensive logistics options, the ConnectBooks + ZonPrep combo can help you:
Discover how better financial visibility and faster operations can transform your Amazon business:
Running an e-commerce business comes with plenty of challenges, but ConnectBooks is here to make your life easier. With real-time insights, seamless integrations, and detailed tracking of your profitability and inventory, you can stay ahead of the game. Whether you’re selling on Amazon, Shopify, Walmart, TikTok or eBay, ConnectBooks helps you manage your finances with 100% accuracy and confidence, so you can focus on growing your business.
Ready to level up? Start making smarter, data-driven decisions every step of the way. Try ConnectBooks Free Today or Schedule a Demo
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